Properties of the Number 81981

Eighty-One Thousand Nine Hundred Eighty-One

Basics

Value: 81980 → 81981 → 81982

Parity: odd

Prime: No

Previous Prime: 81973

Next Prime: 82003

Digit Sum: 27

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 9109

Divisors: 1, 3, 9, 9109, 27327, 81981

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 10100000000111101

Octal: 240075

Duodecimal: 3B539

Hexadecimal: 1403d

Square: 6720884361

Square Root: 286.32324390450736

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

Number of nondecreasing arrangements of n numbers in -(n+3)..(n+3) with sum zero and not more than two numbers equal. A188232

Number of nondecreasing arrangements of 8 numbers in -(n+6)..(n+6) with sum zero and not more than two numbers equal. A188241

T(n,k)=Number of nondecreasing arrangements of n numbers in -(n+k-2)..(n+k-2) with sum zero and not more than two numbers equal. A188236

Primes p such that p+1 is divisible by every nonzero digit of p. A81981