18720720 has 160 divisors (see below), whose sum is σ = 65888640. Its totient is φ = 4945536.

The previous prime is 18720707. The next prime is 18720731. The reversal of 18720720 is 2702781.

It is a Harshad number since it is a multiple of its sum of digits (27).

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 31 ways as a sum of consecutive naturals, for example, 174907 + ... + 175013.

It is an arithmetic number, because the mean of its divisors is an integer number (411804).

Almost surely, 2^18720720 is an apocalyptic number.

18720720 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 18720720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32944320).

18720720 is an abundant number, since it is smaller than the sum of its proper divisors (47167920).

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

18720720 is an equidigital number, since it uses as much as digits as its factorization.

18720720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141 (or 117 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 27.

The square root of 18720720 is about 4326.7447347862. The cubic root of 18720720 is about 265.5262829482.

The spelling of 18720720 in words is "eighteen million, seven hundred twenty thousand, seven hundred twenty".