Properties of the Number 21992

Twenty-One Thousand Nine Hundred Ninety-Two

Basics

Value: 21991 → 21992 → 21993

Parity: even

Prime: No

Previous Prime: 21991

Next Prime: 21997

Digit Sum: 23

Digital Root: 5

Palindrome: No

Factorization: 2 ³ × 2749

Divisors: 1, 2, 4, 8, 2749, 5498, 10996, 21992

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010111101000

Octal: 52750

Duodecimal: 10888

Hexadecimal: 55e8

Square: 483648064

Square Root: 148.29699929533302

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

Real part of absolute Gaussian perfect numbers, in order of increasing magnitude. A102531

Triangle read by rows: T(n,k) is the number of free polyominoes with width n and height 1<=k<=n. A268371

a(n) = ∑_{k <= n/2} binomial(n-2k, 3k+2). A137358

Number of compositions of 5·n-1 into parts 3 and 5. A369846

a(n) = ∑_{k=0..floor(2·n/3)} binomial(2·k,2·n-3·k). A392428

Number of (n+1) X (1+1) arrays of permutations of 0..n·2+1 with each element having directed index change -2,0 -1,0 0,-1 or 1,1. A264622

The number of steps for a walk on a square spiral numbered board when starting on square 1 and stepping to an unvisited square containing the lowest prime number, where the square is within a block of size (2n+1) X (2n+1) centered on the current square. If no unvisited prime numbered squares exist within the block the walk ends. A336494

Number of binary words of length n avoiding distance (i+1) between "1" digits if the i-th bit is set in the binary representation of n. A376091

Number of ballot sequences of length n with exactly 8 fixed points. A239119

Number of compositions of n into parts 1, 6, and 7. A259278

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