18538 has 16 divisors (see below), whose sum is σ = 32256. Its totient is φ = 7920.

The previous prime is 18523. The next prime is 18539. The reversal of 18538 is 83581.

18538 is nontrivially palindromic in base 12.

It is not an unprimeable number, because it can be changed into a prime (18539) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 583 + ... + 613.

It is an arithmetic number, because the mean of its divisors is an integer number (2016).

2¹⁸⁵³⁸ is an apocalyptic number.

18538 is a deficient number, since it is larger than the sum of its proper divisors (13718).

18538 is a wasteful number, since it uses less digits than its factorization.

18538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69.

The product of its digits is 960, while the sum is 25.

The square root of 18538 is about 136.1543242060. The cubic root of 18538 is about 26.4659584253.

Subtracting from 18538 its product of digits (960), we obtain a triangular number (17578 = T₁₈₇).

The spelling of 18538 in words is "eighteen thousand, five hundred thirty-eight".