Properties of the Number 81639

Eighty-One Thousand Six Hundred Thirty-Nine

Basics

Value: 81638 → 81639 → 81640

Parity: odd

Prime: No

Previous Prime: 81637

Next Prime: 81647

Digit Sum: 27

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 47 × 193

Divisors: 1, 3, 9, 47, 141, 193, 423, 579, 1737, 9071

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

5184 Try Today's Challenge

Representations

Binary: 10011111011100111

Octal: 237347

Duodecimal: 3B2B3

Hexadecimal: 13ee7

Square: 6664926321

Square Root: 285.7253926412562

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

Numbers n such that n² is divisible by the sum of the distinct prime divisors of n² + 1. A196219

Number of ways to write n as an ordered sum of 1s, 2s, 3s and 4s such that no 2 precedes any 1 and no 3 precedes any 1 or 2. A123569

Number of ways to place zero or more nonadjacent 1,0 1,1 2,1 polyhexes in any orientation on a planar nXnXn triangular grid. A155217

Class 11+ primes. A81639

Number of (n+1)X(2+1) 0..3 arrays with no 2X2 subblock having the maximum of its diagonal elements greater than the absolute difference of its antidiagonal elements. A251161