18388880 has 40 divisors (see below), whose sum is σ = 43570872. Its totient is φ = 7215104.

The previous prime is 18388879. The next prime is 18388957. The reversal of 18388880 is 8888381.

It can be written as a sum of positive squares in 4 ways, for example, as 173056 + 18215824 = 416^2 + 4268^2 .

It is a tau number, because it is divible by the number of its divisors (40).

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, 2072 + ... + 6408.

Almost surely, 2^18388880 is an apocalyptic number.

18388880 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18388880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21785436).

18388880 is an abundant number, since it is smaller than the sum of its proper divisors (25181992).

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

18388880 is a wasteful number, since it uses less digits than its factorization.

18388880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4403 (or 4397 counting only the distinct ones).

The product of its (nonzero) digits is 98304, while the sum is 44.

The square root of 18388880 is about 4288.2257403266. The cubic root of 18388880 is about 263.9480307866.

The spelling of 18388880 in words is "eighteen million, three hundred eighty-eight thousand, eight hundred eighty".