Properties of the Number 18881

Eighteen Thousand Eight Hundred Eighty-One

Basics

Value: 18880 → 18881 → 18882

Parity: odd

Prime: No

Previous Prime: 18869

Next Prime: 18899

Digit Sum: 26

Digital Root: 8

Palindrome: Yes

Factorization: 79 × 239

Divisors: 1, 79, 239, 18881

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100100111000001

Octal: 44701

Duodecimal: AB15

Hexadecimal: 49c1

Square: 356492161

Square Root: 137.40815114104404

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

Palindromic in bases 5 and 10. A29962

a(n) = least k such that the remainder when 26^k is divided by k is n. A128366

Numbers with mirror symmetry about middle. A6072

Indices of primes in A057137. A120819

T(n,k)=Number of (n+2)X(k+2) 0..1 arrays with no 3x3 subblock diagonal sum 0 or 1 and no antidiagonal sum 0 or 1 and no row sum 1 and no column sum 1. A256029

a(n) = ∑_{1 <= x₁, x₂, x₃ <= n} n/gcd(x₁, x₂, x₃, n). A372952

a(n) = a(n-1) + a(floor(n/2)) + a(ceiling(n/2)). A131205

Odd composite integers m such that A054413(m-J(m,53)) == 0 (mod m), where J(m,53) is the Jacobi symbol. A340096

Greedy frac multiples of π²/6: a(1)=1, ∑_n>=1 frac(a(n)*x) = 1 at x = π²/6. A79937

Sums of 5 distinct powers of 5. A38477