18720724 has 12 divisors (see below), whose sum is σ = 35739648. Its totient is φ = 8509400.

The previous prime is 18720707. The next prime is 18720731. The reversal of 18720724 is 42702781.

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, 212692 + ... + 212779.

It is an arithmetic number, because the mean of its divisors is an integer number (2978304).

Almost surely, 2^18720724 is an apocalyptic number.

It is an amenable number.

18720724 is a deficient number, since it is larger than the sum of its proper divisors (17018924).

18720724 is a wasteful number, since it uses less digits than its factorization.

18720724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 425486 (or 425484 counting only the distinct ones).

The product of its (nonzero) digits is 6272, while the sum is 31.

The square root of 18720724 is about 4326.7451970274. The cubic root of 18720724 is about 265.5263018596.

The spelling of 18720724 in words is "eighteen million, seven hundred twenty thousand, seven hundred twenty-four".