Properties of the Number 21660

Twenty-One Thousand Six Hundred Sixty

Basics

Value: 21659 → 21660 → 21661

Parity: even

Prime: No

Previous Prime: 21649

Next Prime: 21661

Digit Sum: 15

Digital Root: 6

Palindrome: No

Factorization: 2 ² × 3 × 5 × 19 ²

Divisors: 1, 2, 3, 4, 5, 6, 10, 12, 15, 19

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010010011100

Octal: 52234

Duodecimal: 10650

Hexadecimal: 549c

Square: 469155600

Square Root: 147.17336715588183

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

Number of binary [ n,3 ] codes without 0 columns. A34344

Poincaré series for invariant polynomial functions on the space of binary forms of degree 13. A293938

Poincaré series for invariant polynomial functions on the space of binary forms of degree 24. A293943

a(n) = n²*(n² - 1)/6. A8911

Numbers n that raised to the powers from 1 to k (with k>=1) are multiple of the sum of their digits (n raised to k+1 must not be a multiple). Case k=12. A135197

Number of 2 X 2 planar subsets in an n X n X n cube. A270205

a(n) = 15·n². A64761

T(n,k)=Number of nXk arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor. A221245

a(n) = lcm(τ(n), σ(n), pod(n)) where τ(k) is the number of divisors of k (A000005), σ(k) is the sum of divisors of k (A000203) and pod(k) is the product of divisors of k (A007955). A336723

a(n) = lcm(σ(n), pod(n)) where σ(k) = the sum of divisors of k (A000203) and pod(n) = the product of divisors of k (A007955). A324529