Properties of the Number 21568

Twenty-One Thousand Five Hundred Sixty-Eight

Basics

Value: 21567 → 21568 → 21569

Parity: even

Prime: No

Previous Prime: 21563

Next Prime: 21569

Digit Sum: 22

Digital Root: 4

Palindrome: No

Factorization: 2 ⁶ × 337

Divisors: 1, 2, 4, 8, 16, 32, 64, 337, 674, 1348

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010001000000

Octal: 52100

Duodecimal: 10594

Hexadecimal: 5440

Square: 465178624

Square Root: 146.86047800548656

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

a(n) = ((1+sqrt(13))ⁿ + (1-sqrt(13))ⁿ)/2. A125816

Number of partitions p = [x(1), ..., x(k)], where x(1) >= x(2) >= ... >= x(k), of n such that max(x(i) - x(i-1)) <= number of parts of p. A241829

Principal diagonal of the convolution array A213847. A213848

Triangle read by rows: T(n, k) = (k + 1)*T(n-1, k) + ∑_j=k..n-1 T(n-1, j) for k < n, T(n, n) = 1. T(n, k) for n >= 0 and 0 <= k <= n. A242431

p-INVERT of (1,0,0,1,0,0,0,0,0,0,...), where p(S) = 1 - S². A292402

Molien series for symmetrized weight enumerators of self-dual codes over GF(4) + GF(4)u with u² = 0. A92549

θ series of direct sum of 2 copies of 4-dimensional lattice QQF.4.i. A212817

Expansion of ∏_k>=0 (1 + x^{4^k})^{4^(k+1}). A321355

a(n) is the smallest centered n-gonal number with exactly n prime factors (counted with multiplicity). A358926

a(n) = A000695(A014486(n)). A83931