Properties of the Number 81921

Eighty-One Thousand Nine Hundred Twenty-One

Basics

Value: 81920 → 81921 → 81922

Parity: odd

Prime: No

Previous Prime: 81919

Next Prime: 81929

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 3 × 7 × 47 × 83

Divisors: 1, 3, 7, 21, 47, 83, 141, 249, 329, 581

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 10100000000000001

Octal: 240001

Duodecimal: 3B4A9

Hexadecimal: 14001

Square: 6711050241

Square Root: 286.21844804274934

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

a(0) = 6; for n>0, a(n) = 2·a(n-1) - 1. A83575

Numbers containing only 1's and 0's in their base-2, base-3, and base-4 representations. A258981

G.f.: (1+x)/∏_m>0 (1 - x^m). A84376

a(n) = (A001317(2n)-1)/4. A89893

a(n) = 5·4ⁿ+1. A199115

Decimal representation of the x-axis, from the origin to the right edge, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 774", based on the 5-celled von Neumann neighborhood. A283913

Decimal representation of the x-axis, from the origin to the right edge, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 806", based on the 5-celled von Neumann neighborhood. A284144

a(n) = 80·n² + 1. A158776

Results from a change in the rules leading to sequence A097357. A110565

a(0)=0; thereafter a(n) = (3·n+1)*2^n-2+1. A170881