Properties of the Number 18705

Eighteen Thousand Seven Hundred Five

Basics

Value: 18704 → 18705 → 18706

Parity: odd

Prime: No

Previous Prime: 18701

Next Prime: 18713

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 3 × 5 × 29 × 43

Divisors: 1, 3, 5, 15, 29, 43, 87, 129, 145, 215

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100100100010001

Octal: 44421

Duodecimal: A9A9

Hexadecimal: 4911

Square: 349877025

Square Root: 136.7662239004938

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

Fermat pseudoprimes to base 2, also called Sarrus numbers or Poulet numbers. A1567

Euler pseudoprimes: composite numbers n such that 2^(n-1/2) == +-1 (mod n). A6970

Euler-Jacobi pseudoprimes: 2^(n-1/2) == (2 / n) mod n, where (2 / n) is a Jacobi symbol. A47713

Composite numbers k such that k == +-1 (mod 8) and 2^(k-1/2) == 1 (mod k). A6971

Limit of reversed rows of triangle A126347, in which row sums equal Bell numbers (A000110). A126348

Sarrus numbers A001567 that are not Carmichael numbers A002997. A153508

a(n) = (n+1)*(2·n+1)*(3·n+1). A11199

Composite numbers k == 1 (mod 4) such that (1 + i)^k == 1 + i (mod k), where i = sqrt(-1). A270698

Pseudoprimes to base 11. A20139

Increasing gaps between 2-pseudoprimes (upper end). A175737