Properties of the Number 21658

Twenty-One Thousand Six Hundred Fifty-Eight

Basics

Value: 21657 → 21658 → 21659

Parity: even

Prime: No

Previous Prime: 21649

Next Prime: 21661

Digit Sum: 22

Digital Root: 4

Palindrome: No

Factorization: 2 × 7 ² × 13 × 17

Divisors: 1, 2, 7, 13, 14, 17, 26, 34, 49, 91

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010010011010

Octal: 52232

Duodecimal: 1064A

Hexadecimal: 549a

Square: 469068964

Square Root: 147.16657229140046

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

Sum of adjacent Catalan numbers. A5807

Second (k=2) triangle of numbers related to totally asymmetric exclusion process (case α=1, β=1). A115127

Expansion of (1+x)*c(x), c(x) the g.f. of A000108. A167422

Numbers k which have a factorization k = f1·f2*...*fr where the digits of {k, f1, f2, ..., fr} together give 0,1,...,9 exactly once. A370970

Expansion of (1+x²*C)*C, where C = (1-(1-4·x)^1/2)/(2·x) is g.f. for Catalan numbers, A000108. A71716

Third diagonal of array in A059347. A59348

Self-convolution of repeated Catalan numbers. A104722

Numbers k which use half of the ten digits such that they have at least one factorization k=p·q that uses remaining half of the digits that are not in k. A195814

Numbers n = p·q, where n, p, and q together contain all 10 digits at least once. A253172

Coordination sequence for {A₆}* lattice. A8534