72 (number)
Encyclopedia
72 is the natural number
following 71
and preceding 73
. It is half a gross
or 6 dozen
(i.e., 60 in duodecimal
).
(13 + 17 + 19 + 23), as well as the sum of six consecutive primes (5 + 7 + 11 + 13 + 17 + 19). The product of 8 and 9, 72 is a pronic number
.
The sum of Euler's totient function
φ(x) over the first fifteen integers is 72. There are 17 solutions to the equation φ(x) = 72, more than any integer below 72, making it a highly totient number
.
72 is the smallest number whose fifth power is the sum of five smaller fifth powers: 195 + 435 + 465 + 475 + 675 = 725.
The sum of the eighth row of Lozanić's triangle
is 72.
In a plane, the exterior angles of a regular pentagon
measure 72 degrees each.
In base 10, the number 72 is a Harshad number
.
Natural number
In mathematics, the natural numbers are the ordinary whole numbers used for counting and ordering . These purposes are related to the linguistic notions of cardinal and ordinal numbers, respectively...
following 71
71 (number)
71 is the natural number following 70 and preceding 72.-In mathematics:71 is the algebraic degree of Conway's constant, a remarkable number arising in the study of look-and-say sequences....
and preceding 73
73 (number)
73 is the natural number following 72 and preceding 74. In English, it is the smallest integer with twelve letters in its spelled out name.- In mathematics :...
. It is half a gross
Gross (unit)
A gross is equal to a dozen dozen, i.e. 12 × 12 = 144.It can be used in duodecimal counting. The use of gross likely originated from the fact that 144 can be counted on the fingers using the fingertips and first two joints of each finger when marked by the thumb of one hand. The other hand...
or 6 dozen
Dozen
A dozen is a grouping of approximately twelve. The dozen may be one of the earliest primitive groupings, perhaps because there are approximately a dozen cycles of the moon or months in a cycle of the sun or year...
(i.e., 60 in duodecimal
Duodecimal
The duodecimal system is a positional notation numeral system using twelve as its base. In this system, the number ten may be written as 'A', 'T' or 'X', and the number eleven as 'B' or 'E'...
).
In mathematics
Seventy-two is the sum of four consecutive primesPrime number
A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. A natural number greater than 1 that is not a prime number is called a composite number. For example 5 is prime, as only 1 and 5 divide it, whereas 6 is composite, since it has the divisors 2...
(13 + 17 + 19 + 23), as well as the sum of six consecutive primes (5 + 7 + 11 + 13 + 17 + 19). The product of 8 and 9, 72 is a pronic number
Pronic number
A pronic number, oblong number, rectangular number or heteromecic number, is a number which is the product of two consecutive integers, that is, n . The n-th pronic number is twice the n-th triangular number and n more than the n-th square number...
.
The sum of Euler's totient function
Euler's totient function
In number theory, the totient \varphi of a positive integer n is defined to be the number of positive integers less than or equal to n that are coprime to n In number theory, the totient \varphi(n) of a positive integer n is defined to be the number of positive integers less than or equal to n that...
φ(x) over the first fifteen integers is 72. There are 17 solutions to the equation φ(x) = 72, more than any integer below 72, making it a highly totient number
Highly totient number
A highly totient number k is an integer that has more solutions to the equation φ = k, where φ is Euler's totient function, than any integer below it. The first few highly totient numbers are...
.
72 is the smallest number whose fifth power is the sum of five smaller fifth powers: 195 + 435 + 465 + 475 + 675 = 725.
The sum of the eighth row of Lozanić's triangle
Lozanic's triangle
Lozanić's triangle is a triangular array of binomial coefficients in a manner very similar to that of Pascal's triangle...
is 72.
In a plane, the exterior angles of a regular pentagon
Pentagon
In geometry, a pentagon is any five-sided polygon. A pentagon may be simple or self-intersecting. The sum of the internal angles in a simple pentagon is 540°. A pentagram is an example of a self-intersecting pentagon.- Regular pentagons :In a regular pentagon, all sides are equal in length and...
measure 72 degrees each.
In base 10, the number 72 is a Harshad number
Harshad number
A Harshad number, or Niven number in a given number base, is an integer that is divisible by the sum of its digits when written in that base. Harshad numbers were defined by D. R. Kaprekar, a mathematician from India. The word "Harshad" comes from the Sanskrit + , meaning joy-giver. The Niven...
.
In science
- The atomic numberAtomic numberIn chemistry and physics, the atomic number is the number of protons found in the nucleus of an atom and therefore identical to the charge number of the nucleus. It is conventionally represented by the symbol Z. The atomic number uniquely identifies a chemical element...
of hafniumHafniumHafnium is a chemical element with the symbol Hf and atomic number 72. A lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in zirconium minerals. Its existence was predicted by Dmitri Mendeleev in 1869. Hafnium was the penultimate stable... - In degrees Fahrenheit considered to be room temperatureRoom temperature-Comfort levels:The American Society of Heating, Refrigerating and Air-Conditioning Engineers has listings for suggested temperatures and air flow rates in different types of buildings and different environmental circumstances. For example, a single office in a building has an occupancy ratio per...
. - The average number of heartbeats per minute for a resting adult.
- Percentage of water of which the human body is composed.
- The life duration of the ovule is 72 hours.
- The axis of the earth moves of one degree every 72 years compared to stars and to the vault of heaven.
In astronomy
- The 72 Paranatellons, extra-zodiacal constellations that rise and set simultaneously with zodiacal constellations.
- Messier objectMessier objectThe Messier objects are a set of astronomical objects first listed by French astronomer Charles Messier in 1771. The original motivation of the catalogue was that Messier was a comet hunter, and was frustrated by objects which resembled but were not comets...
M72Messier 72Messier 72 is a globular cluster in the Aquarius constellation discovered by Pierre Méchain on August 29, 1780. Charles Messier looked for it on the following October 4 and 5, and included it in his catalog...
, a magnitude 10.0 globular clusterGlobular clusterA globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is...
in the constellationConstellationIn modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
AquariusAquarius (constellation)Aquarius is a constellation of the zodiac, situated between Capricornus and Pisces. Its name is Latin for "water-bearer" or "cup-bearer", and its symbol is , a representation of water....
. - The New General CatalogueNew General CatalogueThe New General Catalogue of Nebulae and Clusters of Stars is a well-known catalogue of deep sky objects in astronomy. It contains 7,840 objects, known as the NGC objects...
object NGC 72, a magnitude 13.5 barred spiral galaxyBarred spiral galaxyA barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars. Bars are found in approximately two-thirds of all spiral galaxies...
in the constellation AndromedaAndromeda (constellation)Andromeda is a constellation in the northern sky. It is named after Andromeda, the princess in the Greek legend of Perseus who was chained to a rock to be eaten by the sea monster Cetus...
. - The Saros number of the solar eclipseSolar eclipseAs seen from the Earth, a solar eclipse occurs when the Moon passes between the Sun and the Earth, and the Moon fully or partially blocks the Sun as viewed from a location on Earth. This can happen only during a new moon, when the Sun and the Moon are in conjunction as seen from Earth. At least...
series which began on -727 August 16 and ended on 752 January. The duration of Saros series 72 was 1478.1 years, and it contained 83 solar eclipses. - The Saros number of the lunar eclipseLunar eclipseA lunar eclipse occurs when the Moon passes behind the Earth so that the Earth blocks the Sun's rays from striking the Moon. This can occur only when the Sun, Earth, and Moon are aligned exactly, or very closely so, with the Earth in the middle. Hence, a lunar eclipse can only occur the night of a...
series which began on -407 June 5 and ended on 891 July. The duration of Saros series 72 was 1298.1 years, and it contained 73 lunar eclipses. - The precession of equinoxes traces out a pair of cones joined at their apices in a cycle of approximately 26,000 years, that is 1 degree every 72 years (approximation to the nearmost integer).
In religion
- The number of languages spoken at the Tower of Babylon.
- The conventional number of scholars translating the Septuagint, according to the legendary account in the "Letter of Aristeas".
- The conventional number of disciples sent forth by Jesus in Luke 10 in some manuscripts (seventy in others).
- The number of names of God, according to KabbalahKabbalahKabbalah/Kabala is a discipline and school of thought concerned with the esoteric aspect of Rabbinic Judaism. It was systematized in 11th-13th century Hachmei Provence and Spain, and again after the Expulsion from Spain, in 16th century Ottoman Palestine...
(see names of God in JudaismNames of God in JudaismIn Judaism, the name of God is more than a distinguishing title; it represents the Jewish conception of the divine nature, and of the relationship of God to the Jewish people and to the world. To demonstrate the sacredness of the names of God, and as a means of showing respect and reverence for...
). - The ShemhamphoraschShemhamphoraschThe Shemhamphorasch is a corruption of the Hebrew term , which was used in tannaitic times to refer to the Tetragrammaton. In early Kabbalah the term was used to designate sometimes a seventy-two Letter name for God, and sometimes a forty two Letter name...
related to the number of the names of God. - The total number of books in the Holy Bible in the CatholicCatholicThe word catholic comes from the Greek phrase , meaning "on the whole," "according to the whole" or "in general", and is a combination of the Greek words meaning "about" and meaning "whole"...
version if the Book of Lamentations is considered part of the Book of Jeremiah. - The current distribution of the Book of RevelationBook of RevelationThe Book of Revelation is the final book of the New Testament. The title came into usage from the first word of the book in Koine Greek: apokalupsis, meaning "unveiling" or "revelation"...
is 22 chapters, adopted since the 13th century, but the oldest known division of the text is that the Greek commentator Andrew of Cesary (6th century) in 72 chapters. - The number of warriors on the Muslim side at the Battle of BadrBattle of BadrThe Battle of Badr , fought Saturday, March 13, 624 AD in the Hejaz region of western Arabia , was a key battle in the early days of Islam and a turning point in Muhammad's struggle with his opponents among the Quraish in Mecca...
. - The number of people martyred along with Imam Hussain at the Battle of KarbalaBattle of KarbalaThe Battle of Karbala took place on Muharram 10, in the year 61 of the Islamic calendar in Karbala, in present day Iraq. On one side of the highly uneven battle were a small group of supporters and relatives of Muhammad's grandson Husain ibn Ali, and on the other was a large military detachment...
. - The number of soldiers who will fight alongside Imam MahdiMahdiIn Islamic eschatology, the Mahdi is the prophesied redeemer of Islam who will stay on Earth for seven, nine or nineteen years- before the Day of Judgment and, alongside Jesus, will rid the world of wrongdoing, injustice and tyranny.In Shia Islam, the belief in the Mahdi is a "central religious...
against the DajjalDajjalal-Masih ad-Dajjal , is an evil figure in Islamic eschatology. He is to appear pretending to be Masih at a time in the future, before Yawm al-Qiyamah , directly comparable to the figures of the Antichrist and Armilus in Christian and Jewish eschatology, respectively.-Name: is a common Arabic word ...
, according to Islamic ahadith are 313 not 72. - The 72 old men of the synagogue, according to the Zohar.
- The number of houriHouriIn Islam, the ḥūr or ḥūrīyah are commonly translated as " companions of equal age ", "lovely eyed", of "modest gaze", "pure beings" or "companions pure" of paradise, denoting humans and jinn who enter paradise after being recreated anew in the hereafter...
each Muslim martyr (or every Muslim male, according to some ahadith) shall receive as companions in Paradise. - The degrees of the Jacob's ladderJacob's LadderJacob's Ladder is a "ladder to heaven", described by biblical Jacob in the Book of GenesisJacob's Ladder may also refer to:* Ladder of Jacob, a pseudepigraphic text of the Old Testament...
were to the number of 72, according to the ZoharZoharThe Zohar is the foundational work in the literature of Jewish mystical thought known as Kabbalah. It is a group of books including commentary on the mystical aspects of the Torah and scriptural interpretations as well as material on Mysticism, mythical cosmogony, and mystical psychology...
. - The 72 disciples of ConfuciusConfuciusConfucius , literally "Master Kong", was a Chinese thinker and social philosopher of the Spring and Autumn Period....
. - ThothThothThoth was considered one of the more important deities of the Egyptian pantheon. In art, he was often depicted as a man with the head of an ibis or a baboon, animals sacred to him. His feminine counterpart was Seshat...
, in an Egyptian creation myth, wins a 72nd of each day of the year from the Moon in a game of draughts, as a favour to NutNut (goddess)In the Ennead of Egyptian mythology, Nut was the goddess of the sky.-Goddess of the sky:...
, the Sky Goddess. He uses these portions to make the five intercalary days on which the remaining Gods and Goddesses are born. - The good god OsirisOsirisOsiris is an Egyptian god, usually identified as the god of the afterlife, the underworld and the dead. He is classically depicted as a green-skinned man with a pharaoh's beard, partially mummy-wrapped at the legs, wearing a distinctive crown with two large ostrich feathers at either side, and...
was enclosed in a coffin by 72 evil disciples and accomplices of SetSet (mythology)Set was in Ancient Egyptian religion, a god of the desert, storms, and foreigners. In later myths he was also the god of darkness, and chaos...
. - It is the number of the Immortals of TaoismTaoismTaoism refers to a philosophical or religious tradition in which the basic concept is to establish harmony with the Tao , which is the mechanism of everything that exists...
. - At the age of the puberty, the young Parsee received the investiture of the sacred cord Kucti made of 72 linens in symbol of the community.
- In Cao DaiCao DaiCao Đài is a syncretistic, monotheistic religion, officially established in the city of Tay Ninh, southern Vietnam, in 1926. Đạo Cao Đài is the religion's shortened name, the full name is Đại Đạo Tam Kỳ Phổ Độ...
, the number of planets between hell and heaven.
In other fields
Seventy-two is also:- The ASCII code for 'H'
- The number of hourHourThe hour is a unit of measurement of time. In modern usage, an hour comprises 60 minutes, or 3,600 seconds...
s in 3 dayDayA day is a unit of time, commonly defined as an interval equal to 24 hours. It also can mean that portion of the full day during which a location is illuminated by the light of the sun...
s. - In dpiDots per inchDots per inch is a measure of spatial printing or video dot density, in particular the number of individual dots that can be placed in a line within the span of 1 inch . The DPI value tends to correlate with image resolution, but is related only indirectly.- DPI measurement in monitor...
, the standard resolution of an Apple Macintosh screen. - In typography, point sizes are measured in 1/72 of an inch, 72-point characters are 1 inch tall.
- The number of the French department SartheSartheSarthe is a French department, named after the Sarthe River.- History :The department was created during the French Revolution on March 4, 1790, pursuant to the law of December 22, 1789, starting from a part of the province of Maine which was divided into two departments, Sarthe to the east and...
. - The designation of USAUnited StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
Interstate 72Interstate 72Interstate 72 is an Interstate Highway in the midwestern United States. Its western terminus is in Hannibal, Missouri, at an intersection with U.S. Route 61; its eastern terminus is at Country Fair Drive in Champaign, Illinois. In 2006, the Illinois General Assembly dedicated all of Interstate 72...
, a freeway that runs from MissouriMissouriMissouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It...
to IllinoisIllinoisIllinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...
, East <> West. - Municipal Okrug 72, a municipal okrug of Frunzensky District of Saint PetersburgSaint PetersburgSaint Petersburg is a city and a federal subject of Russia located on the Neva River at the head of the Gulf of Finland on the Baltic Sea...
, Russia - The registry of the U.S. Navy's nuclear aircraft carrierAircraft carrierAn aircraft carrier is a warship designed with a primary mission of deploying and recovering aircraft, acting as a seagoing airbase. Aircraft carriers thus allow a naval force to project air power worldwide without having to depend on local bases for staging aircraft operations...
USS Abraham Lincoln (CVN-72)USS Abraham Lincoln (CVN-72)USS Abraham Lincoln , is the fifth Nimitz-class supercarrier in the United States Navy. She is the second Navy ship named after former president Abraham Lincoln. Her home port is Everett, Washington.-Construction:...
, named after U.S. President Abraham LincolnAbraham LincolnAbraham Lincoln was the 16th President of the United States, serving from March 1861 until his assassination in April 1865. He successfully led his country through a great constitutional, military and moral crisis – the American Civil War – preserving the Union, while ending slavery, and...
. - The designation of the Soviet T-72T-72The T-72 is a Soviet-designed main battle tank that entered production in 1970. It is developed directly from Obyekt-172, and shares parallel features with the T-64A...
tank. - In the movie The Red ViolinThe Red ViolinThe Red Violin is a 1998 Canadian drama film directed by François Girard. It spans three centuries and five countries as it tells the story of a mysterious violin and its many owners...
, the lot number of the Bussotti red violin at the DuVal auction house. - The year AD 72, 72 BC72 BCYear 72 BC was a year of the pre-Julian Roman calendar. At the time it was known as the Year of the Consulship of Publicola and Lentulus...
, 1972, or any other year ending with "72". - The Rule of 72Rule of 72In finance, the rule of 72, the rule of 70 and the rule of 69 are methods for estimating an investment's doubling time. The rule number is divided by the interest percentage per period to obtain the approximate number of periods required for doubling...
in financeFinance"Finance" is often defined simply as the management of money or “funds” management Modern finance, however, is a family of business activity that includes the origination, marketing, and management of cash and money surrogates through a variety of capital accounts, instruments, and markets created...
. - Book: 72 Hour Hold by Bebe Moore CampbellBebe Moore CampbellBebe Moore Campbell , was the author of three New York Times bestsellers, Brothers and Sisters, Singing in the Comeback Choir, and What You Owe Me, which was also a Los Angeles Times "Best Book of 2001"...
- CD: Seventy Two & Sunny by Uncle KrackerUncle KrackerMatthew Shafer is an American rock musician known as Uncle Kracker. His singles include "Follow Me", "Smile", and "Drift Away". His music was more rap rock-based at the start of his career before turning in a more rock and Top 40 style music direction on later releases.-Biography:Shafer was born...
- Jill ClayburghJill ClayburghJill Clayburgh was an American actress. She received Academy Award nominations for her roles in An Unmarried Woman and Starting Over.-Personal life:...
and LeVar BurtonLeVar BurtonLevardis Robert Martyn Burton, Jr. , professionally known as LeVar Burton, is an American actor, director, producer and author who first came to prominence portraying Kunta Kinte in the 1977 award-winning ABC television miniseries Roots, based on the novel by Alex Haley...
starred in Firestorm: 72 Hours in Oakland (1993) - Alternative music band The Delta 72The Delta 72The Delta 72 were an American alternative music band formed in Washington, DC in the summer of 1994, later relocated to Philadelphia, Pennsylvania....
- New York's Dakota Apartments and Strawberry Fields are by 72nd St. and Central Park WestCentral Park WestCentral Park West is an avenue that runs north-south in the New York City borough of Manhattan, in the United States....
- The Persian classical santurSanturThe santur is a Persian hammered dulcimerIt is a trapezoid-shaped box often made of walnut or different exotic woods. The Persian classical santur has 72 strings. The name santur was first referenced in ancient Persian poetry...
, a hammered dulcimer, has 72 strings in 24 triple-stringed courses. - The number of episodes in the original airing of FuturamaFuturamaFuturama is an American animated science fiction sitcom created by Matt Groening and developed by Groening and David X. Cohen for the Fox Broadcasting Company. The series follows the adventures of a late 20th-century New York City pizza delivery boy, Philip J...
. - The Turin BrakesTurin BrakesTurin Brakes are a modern folk duo, comprising Olly Knights and Gale Paridjanian, hailing from Balham, London. They had a UK top 5 hit with their song "Painkiller ".-1999–2003:...
song, also known as Emergency 72 - The number of members in National Senate of Argentina.
- A Civil Air PatrolCivil Air PatrolCivil Air Patrol is a Congressionally chartered, federally supported, non-profit corporation that serves as the official civilian auxiliary of the United States Air Force . CAP is a volunteer organization with an aviation-minded membership that includes people from all backgrounds, lifestyles, and...
unit in Laramie, WY, RMR-WY-072. - There are 72 demons and other spirits in the goetiaGoetiarefers to a practice which includes the invocation of angels or the evocation of demons, and usage of the term in English largely derives from the 17th century grimoire The Lesser Key of Solomon, which features an Ars Goetia as its first section...
The Lesser Key of SolomonThe Lesser Key of SolomonThe Lesser Key of Solomon or Clavicula Salomonis , is an anonymous 17th-century grimoire, and one of the most popular books of demonology...
. - A form of radio shorthand that roughly translates as meaning "Best wishes"
- A common limit for characters per lineCharacters per lineIn typography and computing characters per line or terminal width refers to the maximal number of monospaced characters that may appear on a single line...
in computing - 72 equal temperament72 equal temperamentIn music, 72 equal temperament, called twelfth-tone, 72-tet, 72-edo, or 72-et, is the tempered scale derived by dividing the octave into twelfth-tones, or in other words 72 equal steps...
is a tuning used in Byzantine musicByzantine musicByzantine music is the music of the Byzantine Empire composed to Greek texts as ceremonial, festival, or church music. Greek and foreign historians agree that the ecclesiastical tones and in general the whole system of Byzantine music is closely related to the ancient Greek system...
and by some modern composers.
In sports and games
- The usual par for an 18 hole golfGolfGolf is a precision club and ball sport, in which competing players use many types of clubs to hit balls into a series of holes on a golf course using the fewest number of strokes....
course, especially those in tournament play. - The number of victories the Chicago BullsChicago BullsThe Chicago Bulls are an American professional basketball team based in Chicago, Illinois, playing in the Central Division of the Eastern Conference in the National Basketball Association . The team was founded in 1966. They play their home games at the United Center...
achieved during the 1995-96 NBA season1995-96 NBA seasonThe 1995–96 NBA season was the 50th season of the National Basketball Association , although the league didn't celebrate this anniversary until the following season...
, which is the National Basketball AssociationNational Basketball AssociationThe National Basketball Association is the pre-eminent men's professional basketball league in North America. It consists of thirty franchised member clubs, of which twenty-nine are located in the United States and one in Canada...
record. - The number of spaces in a game of ParcheesiParcheesiParcheesi is a brand name American adaptation of the Indian Cross and Circle game Pachisi. Created in India perhaps as early as 500 AD, the board game is subtitled Royal Game of India because royalty played using color-costumed members of their harems as pieces on large outdoor boards. Such a court...
, from start space to "home." - The year that the ColosseumColosseumThe Colosseum, or the Coliseum, originally the Flavian Amphitheatre , is an elliptical amphitheatre in the centre of the city of Rome, Italy, the largest ever built in the Roman Empire...
was built.
External links
- Go Figure: What can 72 tell us about life, BBC NewsBBC NewsBBC News is the department of the British Broadcasting Corporation responsible for the gathering and broadcasting of news and current affairs. The department is the world's largest broadcast news organisation and generates about 120 hours of radio and television output each day, as well as online...
, 20 July 2011