18989988 has 24 divisors (see below), whose sum is σ = 44445408. Its totient is φ = 6310656.

The previous prime is 18989959. The next prime is 18990017. The reversal of 18989988 is 88998981.

It is an interprime number because it is at equal distance from previous prime (18989959) and next prime (18990017).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1995 + ... + 6477.

It is an arithmetic number, because the mean of its divisors is an integer number (1851892).

Almost surely, 2^18989988 is an apocalyptic number.

It is an amenable number.

18989988 is an abundant number, since it is smaller than the sum of its proper divisors (25455420).

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

18989988 is a wasteful number, since it uses less digits than its factorization.

18989988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4843 (or 4841 counting only the distinct ones).

The product of its digits is 2985984, while the sum is 60.

The square root of 18989988 is about 4357.7503370432. The cubic root of 18989988 is about 266.7932863962.

The spelling of 18989988 in words is "eighteen million, nine hundred eighty-nine thousand, nine hundred eighty-eight".