Properties of the Number 21724

Twenty-One Thousand Seven Hundred Twenty-Four

Basics

Value: 21723 → 21724 → 21725

Parity: even

Prime: No

Previous Prime: 21713

Next Prime: 21727

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 2 ² × 5431

Divisors: 1, 2, 4, 5431, 10862, 21724

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010011011100

Octal: 52334

Duodecimal: 106A4

Hexadecimal: 54dc

Square: 471932176

Square Root: 147.39063742314164

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

Molien series for full 8 X 8 Siegel modular group H₃ of order 371589120. A27633

Expansion of Molien series for relative invariants of 8-dimensional complex Clifford group. A43330

Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 329", based on the 5-celled von Neumann neighborhood. A271275

If p(x) is the x-th prime, then the n-th set of 4 consecutive sexy prime pairs starts at p(a(n)). A95963

If p(x) is the x-th prime, then the n-th set of 5 consecutive sexy prime pairs starts at p(a(n)). A95964

a(n) = (1/5ⁿ) * ∑_k=0..n² ( (binomial(n², k) * 4^k) (mod 5ⁿ) ). A376534

Expansion of 1/((1-x)(1-3x)(1-10x)(1-12x)). A21724

Number of nX5 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 0 and 1 1 1 vertically. A207892