Cardinal Cardinal number In mathematics, cardinal numbers, or cardinals for short, are a generalization of the natural numbers used to measure the cardinality of sets. The cardinality of a finite set is a natural number – the number of elements in the set. The transfinite cardinal numbers describe the sizes of infinite...	7000 seven thousand
Ordinal Ordinal number In set theory, an ordinal number, or just ordinal, is the order type of a well-ordered set. They are usually identified with hereditarily transitive sets. Ordinals are an extension of the natural numbers different from integers and from cardinals...	7000th seven thousandth
Factorization Factorization In mathematics, factorization or factoring is the decomposition of an object into a product of other objects, or factors, which when multiplied together give the original...
Roman numeral	MM
Roman numeral (Unicode)	MM, mm
Binary Binary numeral system The binary numeral system, or base-2 number system, represents numeric values using two symbols, 0 and 1. More specifically, the usual base-2 system is a positional notation with a radix of 2...	1101101011000
Octal Octal The octal numeral system, or oct for short, is the base-8 number system, and uses the digits 0 to 7. Numerals can be made from binary numerals by grouping consecutive binary digits into groups of three...	15530
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'...	4074
Hexadecimal Hexadecimal In mathematics and computer science, hexadecimal is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 0–9 to represent values zero to nine, and A, B, C, D, E, F to represent values ten to fifteen...	1B58

Selected numbers in the range 7001–7999

• 7021 – triangular number
  Triangular number
  A triangular number or triangle number numbers the objects that can form an equilateral triangle, as in the diagram on the right. The nth triangle number is the number of dots in a triangle with n dots on a side; it is the sum of the n natural numbers from 1 to n...
  
  
• 7043 – Sophie Germain prime
  Sophie Germain prime
  In number theory, a prime number p is a Sophie Germain prime if 2p + 1 is also prime. For example, 23 is a Sophie Germain prime because it is a prime and 2 × 23 + 1 = 47, and 47 is also a prime number...
  
  
• 7056 –
• 7057 – cuban prime of the form x = y + 1
• 7073 – Leyland number
  Leyland number
  In number theory, a Leyland number is a number of the form xy + yx, where x and y are integers greater than 1. The first few Leyland numbers are...
  
  
• 7079 – Sophie Germain prime, safe prime
  Safe prime
  A safe prime is a prime number of the form 2p + 1, where p is also a prime. The first few safe primes are...
  
  
• 7103 – Sophie Germain prime
• 7106 – octahedral number
  Octahedral number
  In number theory, an octahedral number is a figurate number that represents the number of spheres in an octahedron formed from close-packed spheres...
  
  
• 7121 – Sophie Germain prime
• 7140 – triangular number, also 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...
  
   and hence 7140/2=3570 is also a triangular number, tetrahedral number
  Tetrahedral number
  A tetrahedral number, or triangular pyramidal number, is a figurate number that represents a pyramid with a triangular base and three sides, called a tetrahedron...
  
  
• 7151 – Sophie Germain prime
• 7187 – safe prime
• 7192 – weird number
  Weird number
  In number theory, a weird number is a natural number that is abundant but not semiperfect.In other words, the sum of the proper divisors of the number is greater than the number, but no subset of those divisors sums to the number itself.- Examples :The smallest weird number is 70...
  
  
• 7193 – Sophie Germain prime
• 7200 – pentagonal pyramidal number
  Pentagonal pyramidal number
  A pentagonal pyramidal number is a figurate number that represents the number of objects in a pyramid with a pentagonal base. The nth pentagonal pyramidal number is equal to the sum of the first n pentagonal numbers....
  
  
• 7211 – Sophie Germain prime
• 7225 – , centered octagonal number
  Centered octagonal number
  A centered octagonal number is a centered figurate number that represents an octagon with a dot in the center and all other dots surrounding the center dot in successive octagonal layers...
  
  
• 7230 –
• 7246 – centered heptagonal number
  Centered heptagonal number
  A centered heptagonal number is a centered figurate number that represents a heptagon with a dot in the center and all other dots surrounding the center dot in successive heptagonal layers...
  
  
• 7247 – safe prime
• 7260 – triangular number
• 7267 – decagonal number
  Decagonal number
  A decagonal number is a figurate number that represents a decagon. The n-th decagonal number is given by the formulaThe first few decagonal numbers are:...
  
  
• 7272 – Kaprekar number
  Kaprekar number
  In mathematics, a Kaprekar number for a given base is a non-negative integer, the representation of whose square in that base can be split into two parts that add up to the original number again. For instance, 45 is a Kaprekar number, because 45² = 2025 and 20+25 = 45. The Kaprekar numbers are...
  
  
• 7291 – nonagonal number
• 7349 – Sophie Germain prime
• 7351 – cuban prime of the form x = y + 1
• 7381 – triangular number
• 7385 – Keith number
• 7396 –
• 7433 – Sophie Germain prime
• 7471 – centered cube number
  Centered cube number
  A centered cube number is a centered figurate number that represents a cube. The centered cube number for n is given byn^3 + ^3.The first few centered cube numbers are...
  
  
• 7503 – triangular number
• 7523 – balanced prime, safe prime
• 7541 – Sophie Germain prime
• 7559 – safe prime
• 7560 – 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....
  
  
• 7561 – Markov number
  Markov number
  A Markov number or Markoff number is a positive integer x, y or z that is part of a solution to the Markov Diophantine equationx^2 + y^2 + z^2 = 3xyz,\,studied by .The first few Markov numbers are...
  
  
• 7568 – centered heptagonal number
• 7569 – , centered octagonal number
• 7583 – balanced prime
• 7607 – safe prime
• 7612 – decagonal number
• 7614 – nonagonal number
• 7626 – triangular number
• 7643 – Sophie Germain prime, safe prime
• 7647 – Keith number
• 7649 – Sophie Germain prime
• 7691 – Sophie Germain prime
• 7703 – safe prime
• 7714 – square pyramidal number
  Square pyramidal number
  In mathematics, a pyramid number, or square pyramidal number, is a figurate number that represents the number of stacked spheres in a pyramid with a square base...
  
  
• 7727 – safe prime
• 7750 – triangular number
• 7770 – tetrahedral number
• 7744
  7744 (number)
  7,744 is the natural number following 7,743 and preceding 7,745.-In mathematics:7,744 is the square of 88. It is the smallest square number which has no isolated digits. It is also the fourth 1,292-gonal number.88 and 7,744 form a unique pair...
  
  – , square nialpdrome not ending in 0
• 7776 –
• 7777 – Kaprekar number
• 7810 – ISO/IEC 7810 is the ISO
  International Organization for Standardization
  The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...
  
  's standard for physical characteristics of identification cards
• 7823 – Sophie Germain prime, safe prime, balanced prime
• 7825 – magic constant
  Magic constant
  The magic constant or magic sum of a magic square is the sum of numbers in any row, column, and diagonal of the magic square. For example, the magic square shown below has a magic constant of 15....
  
   of n×n normal magic square
  Magic square
  In recreational mathematics, a magic square of order n is an arrangement of n2 numbers, usually distinct integers, in a square, such that the n numbers in all rows, all columns, and both diagonals sum to the same constant. A normal magic square contains the integers from 1 to n2...
  
   and n-Queens Problem
  Eight queens puzzle
  The eight queens puzzle is the problem of placing eight chess queens on an 8×8 chessboard so that no two queens attack each other. Thus, a solution requires that no two queens share the same row, column, or diagonal...
  
   for n = 25.
• 7841 – Sophie Germain prime, balanced prime
• 7875 – triangular number
• 7883 – Sophie Germain prime
• 7897 – centered heptagonal number
• 7900 – Awesome number
• 7901 – Sophie Germain prime
• 7909 – Keith number
• 7912 – weird number
• 7920 – the order of the Mathieu group
  Mathieu group
  In the mathematical field of group theory, the Mathieu groups, named after the French mathematician Émile Léonard Mathieu, are five finite simple groups he discovered and reported in papers in 1861 and 1873; these were the first sporadic simple groups discovered...
  
   M_{11, the smallest sporadic simple group}
• 7921 – , centered octagonal number
• 7944 – nonagonal number
• 7957 – super-Poulet number
• 7965 – decagonal number
• 7979 – highly cototient number
  Highly cototient number
  In number theory, a branch of mathematics, a highly cototient number is a positive integer k which is above one and has more solutions to the equation...