Properties of the Number 21789

Twenty-One Thousand Seven Hundred Eighty-Nine

Basics

Value: 21788 → 21789 → 21790

Parity: odd

Prime: No

Previous Prime: 21787

Next Prime: 21799

Digit Sum: 27

Digital Root: 9

Palindrome: No

Factorization: 3 ⁴ × 269

Divisors: 1, 3, 9, 27, 81, 269, 807, 2421, 7263, 21789

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 101010100011101

Octal: 52435

Duodecimal: 10739

Hexadecimal: 551d

Square: 474760521

Square Root: 147.61097520171052

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

Augmentation of the triangular array A158405. See Comments. A193091

Number of representations of n as a sum of products of pairs of positive integers, n = ∑_k=1..m i_k*j_k with i_k<=j_k, i_k<=i_k+1, j_k<=j_k+1, i_k*j_k<=i_k+1*j_k+1. A212214

a(n) = n³ + 6·n² + 6·n + 1. A90197

Molien series for invariants of finite Coxeter group A₉. A266778

a(n) = sum for all integer partitions of n of the difference between number of different parts and number of different multiplicities. A373243

Number of primitive (aperiodic) step shifted (decimated) sequence structures using a maximum of five different symbols. A56404

Number of permutations of 1..n with displacements restricted to {-5,-4,0,1,2,3}. A189592

Number of ordered triples (w,x,y) with all terms in {1,...,n} and w²+x²+y²>2n. A211644

Expansion of ∑_k>0 (1/(1-x^k)⁶ - 1). A363696

a(n) = A077696(n+1)/A077696(n). A77697