18720544 has 24 divisors (see below), whose sum is σ = 38128860. Its totient is φ = 9037056.

The previous prime is 18720539. The next prime is 18720563. The reversal of 18720544 is 44502781.

It can be written as a sum of positive squares in 2 ways, for example, as 16096144 + 2624400 = 4012^2 + 1620^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9159 + ... + 11014.

Almost surely, 2^18720544 is an apocalyptic number.

It is an amenable number.

18720544 is an abundant number, since it is smaller than the sum of its proper divisors (19408316).

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

18720544 is a wasteful number, since it uses less digits than its factorization.

18720544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20212 (or 20204 counting only the distinct ones).

The product of its (nonzero) digits is 8960, while the sum is 31.

The square root of 18720544 is about 4326.7243961223. The cubic root of 18720544 is about 265.5254508439.

The spelling of 18720544 in words is "eighteen million, seven hundred twenty thousand, five hundred forty-four".