Properties of the Number 20955

Twenty Thousand Nine Hundred Fifty-Five

Basics

Value: 20954 → 20955 → 20956

Parity: odd

Prime: No

Previous Prime: 20947

Next Prime: 20959

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 3 × 5 × 11 × 127

Divisors: 1, 3, 5, 11, 15, 33, 55, 127, 165, 381

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101000111011011

Octal: 50733

Duodecimal: 10163

Hexadecimal: 51db

Square: 439112025

Square Root: 144.75841944425892

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 length n+k 0..3 arrays with at most one downstep in every k consecutive neighbor pairs. A258730

Triangle T(n,k) of number of minimal 2-covers of a labeled n-set that cover k points of that set uniquely (k=2,..,n). A57963

1 + ∑_n>=1 a_n xⁿ = ∏_n>=1 (1-xⁿ)^prime(n). A7441

Number of incongruent ways to tile a 5 X 2n room with 1x2 Tatami mats. At most 3 Tatami mats may meet at a point. A68930

Molien series for invariants of finite Coxeter group A₈. A266777

Smallest integer k >= 0 such that the maximum digit of k² written in factorial base equals n. A301872

a(n) = 676·n - 1. A158393

Number of indecomposable (by shuffling) alternating n-anagrams. A218827

a(n) is the smallest error in trying to solve n⁵ = x⁵ + y⁵: for each n from 2 on, find positive integers·and y, x <= y < n such that |n⁵ - x⁵ - y⁵| is minimal and let a(n) = n⁵ - x⁵ - y⁵. In case of a tie, choose the solution with smallest y. A369855

Triangle read by rows: T(n,k) (n >= 1, 1 <= k <= n) = number of alternating anagrams on n letters (of length 2n) which are decomposable into at most k components. A239895