Properties of the Number 20657

Twenty Thousand Six Hundred Fifty-Seven

Basics

Value: 20656 → 20657 → 20658

Parity: odd

Prime: No

Previous Prime: 20641

Next Prime: 20663

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 7 × 13 × 227

Divisors: 1, 7, 13, 91, 227, 1589, 2951, 20657

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101000010110001

Octal: 50261

Duodecimal: BB55

Hexadecimal: 50b1

Square: 426711649

Square Root: 143.72543268329375

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

Coefficients in a q-analog of the function [LambertW(-2x)/(-2x)]^1/2, as a triangle read by rows. A152550

T(n,k)=Number of nXk 0..3 arrays with no element equal to one plus the sum of elements to its left or zero plus the sum of the elements above it or zero plus the sum of the elements diagonally to its northwest or zero plus the sum of the elements antidiagonally to its northeast, modulo 4. A240760

Nonnegative values·of solutions (x, y) to the Diophantine equation x²+(x+967)² = y². A130017

a(n) is the number of partitions of n such that the number of parts having multiplicity > 1 is a part. A241408

a(n) = 3·n⁴ + 12·n³ + 30·n² + 36·n + 17. A160827

Square array T(n,k), n >= 1, k >= 0, read by antidiagonals downwards, where T(n,k) = ∑_j=1..n j^k * binomial(floor(n/j)+1,2). A356124

Triangle T, read by rows, where row n of T = row n-1 of T^fibonacci(n) with appended '1' for n>=1 starting with a single '1' in row 0. A136170

Column 2 of triangle A136170. A136173

7-distance Pell sequence. A237716

Numbers that are the sum of fourth powers of three distinct positive integers in arithmetic progression. A306214