18918979 has 4 divisors (see below), whose sum is σ = 18960480. Its totient is φ = 18877480.

The previous prime is 18918973. The next prime is 18918983. The reversal of 18918979 is 97981981.

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 18918979 - 2⁵ = 18918947 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18918973) 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, 20059 + ... + 20980.

It is an arithmetic number, because the mean of its divisors is an integer number (4740120).

Almost surely, 2^18918979 is an apocalyptic number.

18918979 is a deficient number, since it is larger than the sum of its proper divisors (41501).

18918979 is an equidigital number, since it uses as much as digits as its factorization.

18918979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41500.

The product of its digits is 326592, while the sum is 52.

The square root of 18918979 is about 4349.5952685279. The cubic root of 18918979 is about 266.4603322293.

The spelling of 18918979 in words is "eighteen million, nine hundred eighteen thousand, nine hundred seventy-nine".