18120720 has 40 divisors (see below), whose sum is σ = 56174976. Its totient is φ = 4832128.

The previous prime is 18120719. The next prime is 18120727. The reversal of 18120720 is 2702181.

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (18120727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37512 + ... + 37991.

Almost surely, 2^18120720 is an apocalyptic number.

18120720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18120720 is an abundant number, since it is smaller than the sum of its proper divisors (38054256).

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

18120720 is a wasteful number, since it uses less digits than its factorization.

18120720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75519 (or 75513 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 18120720 is about 4256.8439012959. The cubic root of 18120720 is about 262.6587158074.

The spelling of 18120720 in words is "eighteen million, one hundred twenty thousand, seven hundred twenty".