Properties of the Number 21087

Twenty-One Thousand Eighty-Seven

Basics

Value: 21086 → 21087 → 21088

Parity: odd

Prime: No

Previous Prime: 21067

Next Prime: 21089

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 3 ³ × 11 × 71

Divisors: 1, 3, 9, 11, 27, 33, 71, 99, 213, 297

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101001001011111

Octal: 51137

Duodecimal: 10253

Hexadecimal: 525f

Square: 444661569

Square Root: 145.21363572337137

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

Numbers k such that 3·k is a partition number. A213365

Number of numbers with 6 decimal digits and sum of digits = n. A90581

a(n) = 3ⁿ*hypergeom([-n/3, (1-n)/3, (2-n)/3], [1, 1], -1). A294035

a(n) = 1331·n - 209. A157444

Nonnegative values·of solutions (x, y) to the Diophantine equation x² + (x+497)² = y². A207077

Output of the linear congruential pseudo-random number generator used in function rand() as described in Kernighan and Ritchie, when seeded with 0. A96554

a(n) is the number of rooted 3-connected bicubic planar maps with 2n vertices. A298358

Row sums of the triangle A322550. A320043

Number of (2+1) X (n+1) 0..2 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing x(i,j)+x(i-1,j) in the j direction. A250757

Number of n X 6 0..1 arrays with each 1 adjacent to 3 or 5 king-move neighboring 1's. A296155