18638898 has 32 divisors (see below), whose sum is σ = 38676096. Its totient is φ = 5983488.

The previous prime is 18638897. The next prime is 18638899. The reversal of 18638898 is 89883681.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (18638897) and next prime (18638899).

It is a self number, because there is not a number n which added to its sum of digits gives 18638898.

It is not an unprimeable number, because it can be changed into a prime (18638897) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24715 + ... + 25457.

It is an arithmetic number, because the mean of its divisors is an integer number (1208628).

Almost surely, 2^18638898 is an apocalyptic number.

18638898 is an abundant number, since it is smaller than the sum of its proper divisors (20037198).

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

18638898 is a wasteful number, since it uses less digits than its factorization.

18638898 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 898.

The product of its digits is 663552, while the sum is 51.

The square root of 18638898 is about 4317.2790041877. The cubic root of 18638898 is about 265.1388758256.

The spelling of 18638898 in words is "eighteen million, six hundred thirty-eight thousand, eight hundred ninety-eight".