Properties of the Number 18531

Eighteen Thousand Five Hundred Thirty-One

Basics

Value: 18530 → 18531 → 18532

Parity: odd

Prime: No

Previous Prime: 18523

Next Prime: 18539

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 3 ² × 29 × 71

Divisors: 1, 3, 9, 29, 71, 87, 213, 261, 639, 2059

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100100001100011

Octal: 44143

Duodecimal: A883

Hexadecimal: 4863

Square: 343397961

Square Root: 136.12861565446113

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 ordered triples (i,j,k) with |i| + |j| + |k| <= n and gcd(i,j,k) <= 1. A100450

a(n) = ∑_d∣n φ(d⁴). A68970

Ulam's spiral (WNW spoke). A143859

G.f. A(x) satisfies: A(x) = 1 / ∏_n>=1 (1 - xⁿ*A(x)^n-1). A210043

a(n) = n*(7·n²-12·n+7)/2. A226451

Least k such that 2^2ⁿ+k is prime. A129786

From a counter moving problem. A4138

Sum of the primes in ordered 3 X 3 prime squares. A105089

Number of 3 X n 0..1 arrays with rows nondecreasing and antidiagonals unimodal. A224134

Number of nX4 0..1 arrays with every element equal to 1, 2, 4, 6 or 7 king-move adjacent elements, with upper left element zero. A298656