Properties of the Number 81686

Eighty-One Thousand Six Hundred Eighty-Six

Basics

Value: 81685 → 81686 → 81687

Parity: even

Prime: No

Previous Prime: 81677

Next Prime: 81689

Digit Sum: 29

Digital Root: 2

Palindrome: No

Factorization: 2 × 11 × 47 × 79

Divisors: 1, 2, 11, 22, 47, 79, 94, 158, 517, 869

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

5184 Try Today's Challenge

Representations

Binary: 10011111100010110

Octal: 237426

Duodecimal: 3B332

Hexadecimal: 13f16

Square: 6672602596

Square Root: 285.80762760990126

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 aperiodic necklaces of n beads of 2 colors, 10 of them black. A32168

a(n) = T(2·n+4, n), array T as in A051168 (a count of Lyndon words). A50182

Composite squarefree numbers n such that p(i)-10 divides n+10, where p(i) are the prime factors of n. A225710

Number of 5-length words w over n-ary alphabet such that for every prefix z of w we have #(z,a_i) = 0 or #(z,a_i) >= #(z,a_j) for all j>i and #(z,a_i) counts the occurrences of the i-th letter in z. A213284

Triangular array T(h,k) for 0 <= k <= h read by rows: T(h,k) = number of binary Lyndon words with k ones and h-k zeros. A51168

a(n) = 7ⁿ - 6ⁿ - 5ⁿ - 4ⁿ + 3·3ⁿ. A81686