Properties of the Number 18381

Eighteen Thousand Three Hundred Eighty-One

Basics

Value: 18380 → 18381 → 18382

Parity: odd

Prime: No

Previous Prime: 18379

Next Prime: 18397

Digit Sum: 21

Digital Root: 3

Palindrome: Yes

Factorization: 3 × 11 × 557

Divisors: 1, 3, 11, 33, 557, 1671, 6127, 18381

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 100011111001101

Octal: 43715

Duodecimal: A779

Hexadecimal: 47cd

Square: 337861161

Square Root: 135.57654664432192

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

Numbers k such that 7·2^k - 1 is prime. A1771

Consider all (2n+1)-digit palindromic primes of the form 10...0M0...01 (so that M is a palindrome with <= 2n-1 digits); a(n) = smallest such M. A100026

Number of nonnegative solutions to x³ + y³ + z³ <= n³. A224215

Composite palindromes whose sum of prime factors is prime (counted with multiplicity). A46365

Palindromes n such that 10n01 is a prime. A99744

a(n) = number of triangles with integer sides i <= j <= k with radius of circumcircle <= n. A331229

Largest palindromic substring in 6ⁿ. A46264

Largest palindromic substring in 7ⁿ. A46265

Palindromic odd composite numbers that are the products of an odd number of distinct primes. A75808

Numbers n such that n¹⁰+10 is prime. A239347