Properties of the Number 21984

Twenty-One Thousand Nine Hundred Eighty-Four

Basics

Value: 21983 → 21984 → 21985

Parity: even

Prime: No

Previous Prime: 21977

Next Prime: 21991

Digit Sum: 24

Digital Root: 6

Palindrome: No

Factorization: 2 ⁵ × 3 × 229

Divisors: 1, 2, 3, 4, 6, 8, 12, 16, 24, 32

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010111100000

Octal: 52740

Duodecimal: 10880

Hexadecimal: 55e0

Square: 483296256

Square Root: 148.2700239428051

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+1)X(k+1) 0..2 arrays with every 2X3 or 3X2 subblock having exactly two equal edges, and new values 0..2 introduced in row major order. A206215

Number of non-unimodal compositions of n into distinct terms. A72707

G.f. A(x) satisfies: x = A(x)-2·A(x)²-2·A(x)³. A276310

Number of nondecreasing integer sequences of length 9 with sum zero and sum of absolute values 2n. A158143

a(n) = [ a(n-1)/(sqrt(6) - 2) ], where a(0) = 1. A24557

Number of nX2 1..4 arrays containing at least one of each value, all equal values connected, rows considered as a single number in nondecreasing order, and columns considered as a single number in increasing order. A166815

Number of n X n symmetric binary matrices with each 1 adjacent to no more than 3 horizontally or vertically neighboring 1's. A191508

Number of (n+1)X5 0..2 arrays with every 2X3 or 3X2 subblock having exactly two equal edges, and new values 0..2 introduced in row major order. A206211

Number of (n+1) X 6 0..2 arrays with every 2 X 3 or 3 X 2 subblock having exactly two equal edges, and new values 0..2 introduced in row major order. A206212

Triangle read by rows: T(n,k) is the number of permutations of {1,...,n} whose longest embedded arithmetic progression has length k. A339941