18188020 has 12 divisors (see below), whose sum is σ = 38194884. Its totient is φ = 7275200.

The previous prime is 18187987. The next prime is 18188033. The reversal of 18188020 is 2088181.

It can be written as a sum of positive squares in 2 ways, for example, as 10099684 + 8088336 = 3178^2 + 2844^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 18188020.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 454681 + ... + 454720.

It is an arithmetic number, because the mean of its divisors is an integer number (3182907).

Almost surely, 2^18188020 is an apocalyptic number.

18188020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18188020 is an abundant number, since it is smaller than the sum of its proper divisors (20006864).

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

18188020 is a wasteful number, since it uses less digits than its factorization.

18188020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 909410 (or 909408 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 28.

The square root of 18188020 is about 4264.7414927519. The cubic root of 18188020 is about 262.9834838573.

The spelling of 18188020 in words is "eighteen million, one hundred eighty-eight thousand, twenty".