18564720 has 80 divisors (see below), whose sum is σ = 58186752. Its totient is φ = 4896000.

The previous prime is 18564683. The next prime is 18564737. The reversal of 18564720 is 2746581.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 24345 + ... + 25095.

Almost surely, 2^18564720 is an apocalyptic number.

18564720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18564720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29093376).

18564720 is an abundant number, since it is smaller than the sum of its proper divisors (39622032).

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

18564720 is a wasteful number, since it uses less digits than its factorization.

18564720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 870 (or 864 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 33.

The square root of 18564720 is about 4308.6796121318. The cubic root of 18564720 is about 264.7866801136.

The spelling of 18564720 in words is "eighteen million, five hundred sixty-four thousand, seven hundred twenty".