Properties of the Number 20813

Twenty Thousand Eight Hundred Thirteen

Basics

Value: 20812 → 20813 → 20814

Parity: odd

Prime: No

Previous Prime: 20809

Next Prime: 20849

Digit Sum: 14

Digital Root: 5

Palindrome: No

Factorization: 13 × 1601

Divisors: 1, 13, 1601, 20813

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101000101001101

Octal: 50515

Duodecimal: 10065

Hexadecimal: 514d

Square: 433180969

Square Root: 144.26711336961034

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

Centered 22-gonal numbers. A69173

Self-inverse permutation of natural numbers: complementary pair ludic/nonludic numbers (A003309/A192607) entangled with the same pair in the opposite order, nonludic/ludic. See Formula. A235491

Expansion of f(-x⁶)³ / (f(-x⁴)² * ψ(x)) in powers of·where φ(), f() are Ramanujan θ functions. A262152

Regular triangle read by rows where T(n, k) is the number of set partitions of {1, ..., n} with no block containing k cyclically successive vertices, n >= 1, 2 <= k <= n + 1. A323955

a(n+1) is the smallest number > a(n) such that the digits of a(n)² are all (with multiplicity) contained in the digits of a(n+1)², with a(0)=2. A67975

Binomial row sums of triangle A191490. A191493

Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 659", based on the 5-celled von Neumann neighborhood. A273386

Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 19. A51984

Expansion of (1-x)/(1+x-x²-2·x³). A78041

G.f. A(x) satisfies: A(x) = 1/(1 + (-x)^a(0)/(1 + (-x)^a(1)/(1 + (-x)^a(2)/(1 + (-x)^a(3)/(1 + ...))))), a continued fraction. A307543