18979818 has 48 divisors (see below), whose sum is σ = 44956128. Its totient is φ = 5306400.

The previous prime is 18979817. The next prime is 18979901. The reversal of 18979818 is 81897981.

It is not an unprimeable number, because it can be changed into a prime (18979817) 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 23 ways as a sum of consecutive naturals, for example, 8433 + ... + 10443.

It is an arithmetic number, because the mean of its divisors is an integer number (936586).

Almost surely, 2^18979818 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18979818, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22478064).

18979818 is an abundant number, since it is smaller than the sum of its proper divisors (25976310).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18979818 is a wasteful number, since it uses less digits than its factorization.

18979818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2051 (or 2040 counting only the distinct ones).

The product of its digits is 290304, while the sum is 51.

The square root of 18979818 is about 4356.5832942800. The cubic root of 18979818 is about 266.7456512558.

The spelling of 18979818 in words is "eighteen million, nine hundred seventy-nine thousand, eight hundred eighteen".