Properties of the Number 20797

Twenty Thousand Seven Hundred Ninety-Seven

Basics

Value: 20796 → 20797 → 20798

Parity: odd

Prime: No

Previous Prime: 20789

Next Prime: 20807

Digit Sum: 25

Digital Root: 7

Palindrome: No

Factorization: 7 × 2971

Divisors: 1, 7, 2971, 20797

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101000100111101

Octal: 50475

Duodecimal: 10051

Hexadecimal: 513d

Square: 432515209

Square Root: 144.21165001483064

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

a(n) = ∑_k=1..n floor(n/k)³. A318742

a(n) = floor(M(g(n-1)+1, ..., g(n))), where M = harmonic mean and g(n) = n³. A227012

a(n) = ceiling((n + 1/2)³). A34131

a(n) is the number of triangles (up to congruence) with integer coordinates that have perimeter strictly less than n. A298121

Strong pseudoprimes to base 55. A20281

Numbers n such that n·2²²⁸¹ - 1 is prime. A265504

Number of walks within N³ (the first octant of Z³) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 0, 0), (0, 1, 1), (1, -1, -1), (1, 1, -1)}. A148853

Indices j in A000040 such that j is an odd composite and the distinct digits of the prime A000040(j) are in increasing order. A155775

Expansion of e.g.f. 1 / sqrt(1 - 2·x * (exp(x) - 1)). A375695

Number of permutations in S_n with longest increasing subsequence of length <= 4. A47889