Properties of the Number 51220

Fifty-One Thousand Two Hundred Twenty

Basics

Value: 51219 → 51220 → 51221

Parity: even

Prime: No

Previous Prime: 51217

Next Prime: 51229

Digit Sum: 10

Digital Root: 1

Palindrome: No

Factorization: 2 ² × 5 × 13 × 197

Divisors: 1, 2, 4, 5, 10, 13, 20, 26, 52, 65

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 1100100000010100

Octal: 144024

Duodecimal: 25784

Hexadecimal: c814

Square: 2623488400

Square Root: 226.3183598385248

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

T(n,k) is the number of (n+1) X (k+1) 0..5 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 3, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings). A235026

a(n) = Pell(n)*A028594(n) for n>=1, with a(0)=1, where A028594 lists the coefficients in (theta₃(x)*theta₃(7·x)+theta₂(x)*theta₂(7·x))². A209456

a(n) = ∑_d∣n d^n/d * binomial(n/d,d). A376016

Numerator of Hermite(n, 13/21). A159762

Number of (n+1) X (3+1) 0..5 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 3, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings). A235021

Number of (n+1) X (4+1) 0..5 arrays with every 2 X 2 subblock having its diagonal sum differing from its antidiagonal sum by 3, with no adjacent elements equal (constant-stress tilted 1 X 1 tilings). A235022

Modified Sisyphus function of order 4: a(n) is the concatenation of (number of digits of n)(number digits of n congruent to 0 modulo 4)(number of digits of n congruent to 1 modulo 4)(number of digits of n congruent to 2 modulo 4)(number of digits of n congruent to 3 modulo 4). A352751

Numbers of the form 9^x-y² >= 0. A51220