Properties of the Number 81391

Eighty-One Thousand Three Hundred Ninety-One

Basics

Value: 81390 → 81391 → 81392

Parity: odd

Prime: No

Previous Prime: 81373

Next Prime: 81401

Digit Sum: 22

Digital Root: 4

Palindrome: No

Factorization: 199 × 409

Divisors: 1, 199, 409, 81391

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 10011110111101111

Octal: 236757

Duodecimal: 3B127

Hexadecimal: 13def

Square: 6624494881

Square Root: 285.29107942590844

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

Solution of the complementary equation a(n) = a(n-1) + a(n-2) + b(n)², where a(0) = 2, a(1) = 4, b(0) = 1, b(1) = 3, b(2) = 5, and (a(n)) and (b(n)) are increasing complementary sequences. A296249

Numbers whose base-5 representation has exactly 8 runs. A43608

Numbers k such that the central binomial coefficient C(2·k,k) has only one prime divisor whose exponent exceeds one. A81391

Number of length 4+2 0..n arrays with the sum of the maximum minus the minimum of adjacent triples multiplied by some arrangement of +-1 equal to zero. A252180