18158131 has 4 divisors (see below), whose sum is σ = 18205200. Its totient is φ = 18111064.

The previous prime is 18158113. The next prime is 18158137. The reversal of 18158131 is 13185181.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18158131 - 2⁵ = 18158099 is a prime.

It is a super-2 number, since 2×18158131² = 659435442826322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 18158131.

It is not an unprimeable number, because it can be changed into a prime (18158137) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22951 + ... + 23728.

It is an arithmetic number, because the mean of its divisors is an integer number (4551300).

Almost surely, 2^18158131 is an apocalyptic number.

18158131 is a deficient number, since it is larger than the sum of its proper divisors (47069).

18158131 is an equidigital number, since it uses as much as digits as its factorization.

18158131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47068.

The product of its digits is 960, while the sum is 28.

The square root of 18158131 is about 4261.2358535993. The cubic root of 18158131 is about 262.8393482671.

The spelling of 18158131 in words is "eighteen million, one hundred fifty-eight thousand, one hundred thirty-one".