Properties of the Number 20817

Twenty Thousand Eight Hundred Seventeen

Basics

Value: 20816 → 20817 → 20818

Parity: odd

Prime: No

Previous Prime: 20809

Next Prime: 20849

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 3 ⁴ × 257

Divisors: 1, 3, 9, 27, 81, 257, 771, 2313, 6939, 20817

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101000101010001

Octal: 50521

Duodecimal: 10069

Hexadecimal: 5151

Square: 433347489

Square Root: 144.2809758769326

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

List of codewords in binary lexicode with Hamming distance 6 written as decimal numbers. A75934

Number of partitions p of n such that (number of numbers in p of form 3k+1) < (number of numbers in p of form 3k+2). A241737

Number of integer partitions of n whose parts plus 1 are relatively prime. A318980

Expansion of (1-x-sqrt(1-6x-3x²))/(2x). A156016

Composite numbers for which A324644(n)/A324198(n) = 2 and σ(n) == 2 (mod 4). A371082

G.f. A(x) satisfies: 3ⁿ + 1 = ∑_k=0..n [x^k]A(x)ⁿ and also satisfies: (3+z)ⁿ + (1+z)ⁿ - zⁿ = ∑_k=0..n [x^k](A(x) + z·x)ⁿ for all z, where [x^k]A(x)ⁿ denotes the coefficient of x^k in A(x)ⁿ. A100239

∑_n>=0 a(n) * xⁿ / (n!)² = exp(BesselI(0,2·sqrt(x))³ - 1). A336636

The arithmetic mean of the n-th and (n+1)-st cubes, rounded down. A147656

Euler transform of period 5 sequence [ 2, 1, 1, 2, 1, ...]. A205183

A simple grammar. A52814