Properties of the Number 81320

Eighty-One Thousand Three Hundred Twenty

Basics

Value: 81319 → 81320 → 81321

Parity: even

Prime: No

Previous Prime: 81307

Next Prime: 81331

Digit Sum: 14

Digital Root: 5

Palindrome: No

Factorization: 2 ³ × 5 × 19 × 107

Divisors: 1, 2, 4, 5, 8, 10, 19, 20, 38, 40

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 10011110110101000

Octal: 236650

Duodecimal: 3B088

Hexadecimal: 13da8

Square: 6612942400

Square Root: 285.1666179622012

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

Larger of amicable pair m < n defined by t(n) = m and t(m) = n where t(n) = ψ(n) - n and ψ(n) = A001615(n) is the Dedekind ψ function. A323330

a(n) = ((5+sqrt(2))*(4+sqrt(2))ⁿ + (5-sqrt(2))*(4-sqrt(2))ⁿ)/2. A162271

Let s denote the sum of the abundant numbers in the aliquot parts of x. Sequence lists numbers·such that σ(s) = usigma(x), where usigma(x) is the sum of the unitary divisors of x (A034448). A258135

Numbers n such that there are exactly 4 primes p such that floor(n·log(n))+1<=p<=floor((n+1)*log(n+1))-1. A68362

Array read by antidiagonals: T(n,k) (n>=1, k>=1) = number of ways to select four points from an n X k grid so that three of them form a triangle of nonzero area and the extra point is strictly inside the triangle. A334709

Largest 3-smooth divisor of n-th Fibonacci number. A81320