18508 has 12 divisors (see below), whose sum is σ = 37072. Its totient is φ = 7920.

The previous prime is 18503. The next prime is 18517. The reversal of 18508 is 80581.

18508 is an admirable number.

It is a hoax number, since the sum of its digits (22) coincides with the sum of the digits of its distinct prime factors.

It is a nialpdrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (18503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 303 + ... + 358.

2¹⁸⁵⁰⁸ is an apocalyptic number.

It is an amenable number.

18508 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18536).

18508 is a wasteful number, since it uses less digits than its factorization.

18508 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 672 (or 670 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 22.

The square root of 18508 is about 136.0441104936. The cubic root of 18508 is about 26.4516741186.

The spelling of 18508 in words is "eighteen thousand, five hundred eight".