18188840 has 16 divisors (see below), whose sum is σ = 40924980. Its totient is φ = 7275520.

The previous prime is 18188839. The next prime is 18188843. The reversal of 18188840 is 4888181.

It can be written as a sum of positive squares in 2 ways, for example, as 15570916 + 2617924 = 3946^2 + 1618^2 .

It is a junction number, because it is equal to n+sod(n) for n = 18188794 and 18188803.

It is not an unprimeable number, because it can be changed into a prime (18188843) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 227321 + ... + 227400.

Almost surely, 2^18188840 is an apocalyptic number.

18188840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18188840 is an abundant number, since it is smaller than the sum of its proper divisors (22736140).

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

18188840 is a wasteful number, since it uses less digits than its factorization.

18188840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 454732 (or 454728 counting only the distinct ones).

The product of its (nonzero) digits is 16384, while the sum is 38.

The square root of 18188840 is about 4264.8376287967. The cubic root of 18188840 is about 262.9874359682.

The spelling of 18188840 in words is "eighteen million, one hundred eighty-eight thousand, eight hundred forty".