18409972 has 12 divisors (see below), whose sum is σ = 36820000. Its totient is φ = 7889976.

The previous prime is 18409969. The next prime is 18409987. The reversal of 18409972 is 27990481.

18409972 is an admirable number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 328722 + ... + 328777.

Almost surely, 2^18409972 is an apocalyptic number.

It is an amenable number.

18409972 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

18409972 is a wasteful number, since it uses less digits than its factorization.

18409972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 657510 (or 657508 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 18409972 is about 4290.6843277034. The cubic root of 18409972 is about 264.0489081411.

The spelling of 18409972 in words is "eighteen million, four hundred nine thousand, nine hundred seventy-two".