Properties of the Number 20956

Twenty Thousand Nine Hundred Fifty-Six

Basics

Value: 20955 → 20956 → 20957

Parity: even

Prime: No

Previous Prime: 20947

Next Prime: 20959

Digit Sum: 22

Digital Root: 4

Palindrome: No

Factorization: 2 ² × 13 ² × 31

Divisors: 1, 2, 4, 13, 26, 31, 52, 62, 124, 169

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101000111011100

Octal: 50734

Duodecimal: 10164

Hexadecimal: 51dc

Square: 439153936

Square Root: 144.76187343358058

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 the second largest parts of the partitions of n into 9 squarefree parts. A326531

Expansion of 1/((1-x)*(1-x²)²*(1-x³)²*(1-x⁴)²*(1-x⁵)*(1-x⁶)). A45513

T(n,k)=Number of length n sequences p(i=0..n-1) with 0<=p(i)<=i and having exactly k maxima. A181229

a(n) = 2·n*(16·n - 13). A263228

Coefficients in the power series expansion of A(x) = ∑_n=-oo..+oo n*(n+1)*(n+2)/6·x^3·n * (1 - xⁿ)^n-2. A357156

G.f. A(x) satisfies A(x)² = A(x²) + 2·A(x³). A377255

a(n) is the smallest integer k such that the n-th (backward) difference of the partition sequence A000041 is positive from k onwards. A155861

a(n) = 10·n³ - 6·n². A6592

Sum of squares of entries of Wilkinson's eigenvalue test matrix of order 2n+1. A59834

a(n) = 4ⁿ + 5ⁿ + 7ⁿ. A74562