18404640 has 72 divisors (see below), whose sum is σ = 62810748. Its totient is φ = 4907520.

The previous prime is 18404627. The next prime is 18404653. The reversal of 18404640 is 4640481.

18404640 is a `hidden beast` number, since 18 + 4 + 0 + 4 + 640 = 666.

It is an interprime number because it is at equal distance from previous prime (18404627) and next prime (18404653).

It can be written as a sum of positive squares in 2 ways, for example, as 18352656 + 51984 = 4284^2 + 228^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4951 + ... + 7830.

Almost surely, 2^18404640 is an apocalyptic number.

18404640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18404640 is an abundant number, since it is smaller than the sum of its proper divisors (44406108).

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

18404640 is a wasteful number, since it uses less digits than its factorization.

18404640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12802 (or 12791 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 18404640 is about 4290.0629366013. The cubic root of 18404640 is about 264.0234139013.

It can be divided in two parts, 18404 and 640, that added together give a square (19044 = 138²).

The spelling of 18404640 in words is "eighteen million, four hundred four thousand, six hundred forty".