Properties of the Number 81918

Eighty-One Thousand Nine Hundred Eighteen

Basics

Value: 81917 → 81918 → 81919

Parity: even

Prime: No

Previous Prime: 81901

Next Prime: 81919

Digit Sum: 27

Digital Root: 9

Palindrome: Yes

Factorization: 2 × 3 ³ × 37 × 41

Divisors: 1, 2, 3, 6, 9, 18, 27, 37, 41, 54

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

8109 Try Today's Challenge

Representations

Binary: 10011111111111110

Octal: 237776

Duodecimal: 3B4A6

Hexadecimal: 13ffe

Square: 6710558724

Square Root: 286.21320724243316

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(n) = 5·2ⁿ - 2. A51633

a(n) = 5·2^n-2 - 2 for n > 1, with a(1) = 1. A131051

Numbers n such that n and π(n) (A000720) are palindromic. A103357

Start with 1, then alternately add 2 or double. A123208

Base 10 palindromes that start with 8. A43043

Row sums of triangle A134061. A134062

a(n) is the smallest k > 0 such that the first n multiples of k have the same sum of digits, but (n+1)k has a different one. a(n)=0 if no such k exists. A238088

Number of palindromes (in base 4) below 4ⁿ. A117863

a(n) is the smallest even k >= 2 such that the first n multiples of k have the same sum of digits, but (n + 1)*k has a different one. a(n) = 0 if no such k exists. A237994

a(n) is the smallest decimal palindrome with Hamming weight n (i.e., with exactly n 1's when written in binary). A354480