Properties of the Number 21972

Twenty-One Thousand Nine Hundred Seventy-Two

Basics

Value: 21971 → 21972 → 21973

Parity: even

Prime: No

Previous Prime: 21961

Next Prime: 21977

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 2 ² × 3 × 1831

Divisors: 1, 2, 3, 4, 6, 12, 1831, 3662, 5493, 7324

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010111010100

Octal: 52724

Duodecimal: 10870

Hexadecimal: 55d4

Square: 482768784

Square Root: 148.22955170950223

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

T(n,k)=Number of (n+2)X(k+2) binary arrays with consecutive windows of three bits considered as a binary number nondecreasing in every row and column. A202461

Numbers that are the sum of eight fourth powers in nine or more ways. A345584

Numbers that are the sum of eight fourth powers in exactly nine ways. A345841

G.f. satisfies A(A(x)) = F(x), where F(x) is the g.f. for A001787(n) = n·2^n-1. A309509

E.g.f. satisfies A(x) = 1/(1 - x·exp(x) * A(x))³. A377504

Number of compositions of n into distinct parts with exactly six descents. A241725

a(n) = 10000·log(n) rounded to nearest integer. A4244

Number of (n+2) X 5 binary arrays with consecutive windows of three bits considered as a binary number nondecreasing in every row and column. A202456

Number of (n+2) X 9 binary arrays with consecutive windows of three bits considered as a binary number nondecreasing in every row and column. A202460

a(n) = floor(10000·log(n)). A4243