18638994 has 16 divisors (see below), whose sum is σ = 40667040. Its totient is φ = 5648160.

The previous prime is 18638989. The next prime is 18638999. The reversal of 18638994 is 49983681.

It is an interprime number because it is at equal distance from previous prime (18638989) and next prime (18638999).

It is not an unprimeable number, because it can be changed into a prime (18638999) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 141139 + ... + 141270.

It is an arithmetic number, because the mean of its divisors is an integer number (2541690).

Almost surely, 2^18638994 is an apocalyptic number.

18638994 is an abundant number, since it is smaller than the sum of its proper divisors (22028046).

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

18638994 is a wasteful number, since it uses less digits than its factorization.

18638994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 282425.

The product of its digits is 373248, while the sum is 48.

The square root of 18638994 is about 4317.2901222874. The cubic root of 18638994 is about 265.1393310258.

The spelling of 18638994 in words is "eighteen million, six hundred thirty-eight thousand, nine hundred ninety-four".