720 (number)
Encyclopedia
Seven hundred twenty is the natural number
following 719 and preceding 721.
It is 6! (6 factorial
), a composite number
with thirty divisor
s, more than any number below, making it a highly composite number
. It is a Harshad number
in every base from binary to decimal.
720 is expressible as the product of consecutive integers in two different ways: 720 = 1 × 2 × 3 × 4 × 5 × 6 = 6!, and 720 = 8 × 9 × 10.
There are 49 solutions to the equation φ
(x) = 720, more than any integer below it, making 720 a highly totient number
.
720 is a 241-gonal number
.
For the year AD, see 720
.
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 719 and preceding 721.
It is 6! (6 factorial
Factorial
In mathematics, the factorial of a non-negative integer n, denoted by n!, is the product of all positive integers less than or equal to n...
), a composite number
Composite number
A composite number is a positive integer which has a positive divisor other than one or itself. In other words a composite number is any positive integer greater than one that is not a prime number....
with thirty divisor
Divisor
In mathematics, a divisor of an integer n, also called a factor of n, is an integer which divides n without leaving a remainder.-Explanation:...
s, more than any number below, making it a highly composite number
Highly composite number
A highly composite number is a positive integer with more divisors than any positive integer smaller than itself.The initial or smallest twenty-one highly composite numbers are listed in the table at right....
. It 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 every base from binary to decimal.
720 is expressible as the product of consecutive integers in two different ways: 720 = 1 × 2 × 3 × 4 × 5 × 6 = 6!, and 720 = 8 × 9 × 10.
There are 49 solutions to the equation φ
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...
(x) = 720, more than any integer below it, making 720 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...
.
720 is a 241-gonal number
Polygonal number
In mathematics, a polygonal number is a number represented as dots or pebbles arranged in the shape of a regular polygon. The dots were thought of as alphas . These are one type of 2-dimensional figurate numbers.- Definition and examples :...
.
In other fields
720 is- A common vertical display resolutionDisplay resolutionThe display resolution of a digital television or display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by all different factors in cathode ray tube , flat panel or projection...
for HDTVHigh-definition televisionHigh-definition television is video that has resolution substantially higher than that of traditional television systems . HDTV has one or two million pixels per frame, roughly five times that of SD...
(see 720i and 720p720p720p is the shorthand name for 1280x720, a category of High-definition television video modes having a resolution of 1080 or 720p and a progressive scan...
). - 720 and above is a good credit scoreCredit scoreA credit score is a numerical expression based on a statistical analysis of a person's credit files, to represent the creditworthiness of that person...
. - 720° is two full rotations; the term "720" is a skateboarding trickSkateboarding trickA skateboarding trick, or simply a trick is a maneuver performed on a skateboard while skateboarding. Learning and perfecting new tricks is the primary goal of many skateboarders, for whom most of the time spent skateboarding is spent on tricks....
. - 720°720°720 Degrees, or 720°, is a 1986 arcade game by Atari Games. 720°, a skateboarding game, is notable in that along with BMX Simulator, it is one of the first extreme sports video games, and has a unique timed structure that requires the player score points in order to keep the game going...
is also the name of a skateboarding video game. - 720 is a dual area code in the Denver Metro Area along with 303.
- 720° is the sum of all the defects, of any polyhedronPolyhedronIn elementary geometry a polyhedron is a geometric solid in three dimensions with flat faces and straight edges...
. - 720 is considered a sacred number amongst owners of Lotus sports cars due to it being the estimated unladen weight (kg) of a road-ready Series 1 Elise
For the year AD, see 720
720
Year 720 was a leap year starting on Monday of the Julian calendar. The denomination 720 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.- Asia :* The Nihon Shoki , one of the oldest history...
.