Properties of the Number 18391

Eighteen Thousand Three Hundred Ninety-One

Basics

Value: 18390 → 18391 → 18392

Parity: odd

Prime: No

Previous Prime: 18379

Next Prime: 18397

Digit Sum: 22

Digital Root: 4

Palindrome: No

Factorization: 53 × 347

Divisors: 1, 53, 347, 18391

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100011111010111

Octal: 43727

Duodecimal: A787

Hexadecimal: 47d7

Square: 338228881

Square Root: 135.61342116472102

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

Triangular array T(n,k), read by rows: coefficients of strong divisibility sequence of polynomials p(1,x) = 1, p(2,x) = 1 + 2·x, p(n,x) = u·p(n-1,x) + v·p(n-2,x) for n >= 3, where u = p(2,x), v = 1 + 3·x². A368518

Positive integers of the form (7·m²+1)/11. A179370

Odd numbers m that are neither of the form p + 2^k nor of the form p - 2^k with 2^k < m, k >= 1, and p prime. A255967

Numerators of the difference between the squarefree totient analogs of the harmonic numbers and the harmonic numbers: F_n-H_n. A138320

a(n) = A273059(4n+2). A275918

a(n) = 38·n² - 1. A158596

Numerator of Laguerre(n, 6). A160631

Number of palindromic semiprimes less than 10ⁿ. A108505

Numbers k such that k and k² use only the digits 1, 2, 3, 8 and 9. A136984

Numbers k such that k!6 + 6 is prime, where k!6 is the sextuple factorial number (A085158 ). A287956