18791138 has 12 divisors (see below), whose sum is σ = 29467158. Its totient is φ = 8986560.

The previous prime is 18791107. The next prime is 18791141. The reversal of 18791138 is 83119781.

It can be written as a sum of positive squares in only one way, i.e., 16949689 + 1841449 = 4117^2 + 1357^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7823 + ... + 9938.

Almost surely, 2^18791138 is an apocalyptic number.

18791138 is a deficient number, since it is larger than the sum of its proper divisors (10676020).

18791138 is a wasteful number, since it uses less digits than its factorization.

18791138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17809 (or 17786 counting only the distinct ones).

The product of its digits is 12096, while the sum is 38.

The square root of 18791138 is about 4334.8746233311. The cubic root of 18791138 is about 265.8587921447.

The spelling of 18791138 in words is "eighteen million, seven hundred ninety-one thousand, one hundred thirty-eight".