18388916 has 48 divisors (see below), whose sum is σ = 40454400. Its totient is φ = 7267680.

The previous prime is 18388879. The next prime is 18388957. The reversal of 18388916 is 61988381.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17321 + ... + 18351.

It is an arithmetic number, because the mean of its divisors is an integer number (842800).

Almost surely, 2^18388916 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18388916, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20227200).

18388916 is an abundant number, since it is smaller than the sum of its proper divisors (22065484).

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

18388916 is a wasteful number, since it uses less digits than its factorization.

18388916 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1069 (or 1053 counting only the distinct ones).

The product of its digits is 82944, while the sum is 44.

The square root of 18388916 is about 4288.2299378648. The cubic root of 18388916 is about 263.9482030306.

The spelling of 18388916 in words is "eighteen million, three hundred eighty-eight thousand, nine hundred sixteen".