18381155 has 16 divisors (see below), whose sum is σ = 24161760. Its totient is φ = 13340928.

The previous prime is 18381149. The next prime is 18381173. The reversal of 18381155 is 55118381.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 18381155 - 2⁸ = 18380899 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1439 + ... + 6231.

It is an arithmetic number, because the mean of its divisors is an integer number (1510110).

Almost surely, 2^18381155 is an apocalyptic number.

18381155 is a deficient number, since it is larger than the sum of its proper divisors (5780605).

18381155 is a wasteful number, since it uses less digits than its factorization.

18381155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4870.

The product of its digits is 4800, while the sum is 32.

The square root of 18381155 is about 4287.3249235392. The cubic root of 18381155 is about 263.9110648933.

The spelling of 18381155 in words is "eighteen million, three hundred eighty-one thousand, one hundred fifty-five".