18155979 has 12 divisors (see below), whose sum is σ = 26656032. Its totient is φ = 11905200.

The previous prime is 18155957. The next prime is 18155981. The reversal of 18155979 is 97955181.

It is not a de Polignac number, because 18155979 - 2¹⁵ = 18123211 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18155939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15987 + ... + 17084.

It is an arithmetic number, because the mean of its divisors is an integer number (2221336).

Almost surely, 2^18155979 is an apocalyptic number.

18155979 is a deficient number, since it is larger than the sum of its proper divisors (8500053).

18155979 is a wasteful number, since it uses less digits than its factorization.

18155979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33138 (or 33135 counting only the distinct ones).

The product of its digits is 113400, while the sum is 45.

The square root of 18155979 is about 4260.9833372122. The cubic root of 18155979 is about 262.8289644410.

The spelling of 18155979 in words is "eighteen million, one hundred fifty-five thousand, nine hundred seventy-nine".