Properties of the Number 21630

Twenty-One Thousand Six Hundred Thirty

Basics

Value: 21629 → 21630 → 21631

Parity: even

Prime: No

Previous Prime: 21617

Next Prime: 21647

Digit Sum: 12

Digital Root: 3

Palindrome: No

Factorization: 2 × 3 × 5 × 7 × 103

Divisors: 1, 2, 3, 5, 6, 7, 10, 14, 15, 21

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010001111110

Octal: 52176

Duodecimal: 10626

Hexadecimal: 547e

Square: 467856900

Square Root: 147.07141122597554

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: No

Perfect Number: No

Special

Kaprekar Constant: No

Munchausen Constant: No

Armstrong Number: No

Kaprekar Number: No

Catalan Number: No

Vampire Number: No

Taxicab Number: No

Super Prime: No

Friedman Number: No

Fermat Number: No

Cullen Number: No

OEIS Sequences

Consider the Diophantine equation x³ + y³ = z³ + 1 (1 < x < y < z) or 'Fermat near misses'. Sequence gives values of z in monotonic increasing order. A50791

Cube of lower triangular matrix of A056857 (successive equalities in set partitions of n). A78938

Number T(n,k) of equivalence classes of ways of placing k 9 X 9 tiles in an n X n square under all symmetry operations of the square; irregular triangle T(n,k), n>=9, 0<=k<=floor(n/9)², read by rows. A236936

Subsequence of 'Fermat near misses' which is generated by a simple formula based on the cubic binomial expansion along with formulas for the corresponding terms in the expression, x³ + y³ = z³ + 1. A141326

6 times octagonal numbers: a(n) = 6·n*(3·n-2). A153796

a(n) = A220371(n)/(4·A220371(n-1)). A193365

Integer c such that (a³ + b³ - c³)² = 1 where a,b,c are integers greater than 2. A281224

Number of nonempty subsets of {1,2,...,n} in which exactly 3/5 of the elements are <= n/2. A47167

A071605(n)/(n-1)!. A135474

a(n) = 441·n² + 21. A158603