18538979 has 4 divisors (see below), whose sum is σ = 18595320. Its totient is φ = 18482640.

The previous prime is 18538969. The next prime is 18538981. The reversal of 18538979 is 97983581.

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 18538979 - 2¹² = 18534883 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18538909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27674 + ... + 28335.

It is an arithmetic number, because the mean of its divisors is an integer number (4648830).

Almost surely, 2^18538979 is an apocalyptic number.

18538979 is a deficient number, since it is larger than the sum of its proper divisors (56341).

18538979 is an equidigital number, since it uses as much as digits as its factorization.

18538979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56340.

The product of its digits is 544320, while the sum is 50.

The square root of 18538979 is about 4305.6914659553. The cubic root of 18538979 is about 264.6642431013.

The spelling of 18538979 in words is "eighteen million, five hundred thirty-eight thousand, nine hundred seventy-nine".