18240720 has 40 divisors (see below), whose sum is σ = 56546976. Its totient is φ = 4864128.

The previous prime is 18240713. The next prime is 18240743. The reversal of 18240720 is 2704281.

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

It is a super-2 number, since 2×18240720² = 665447732236800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37762 + ... + 38241.

Almost surely, 2^18240720 is an apocalyptic number.

18240720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18240720 is an abundant number, since it is smaller than the sum of its proper divisors (38306256).

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

18240720 is a wasteful number, since it uses less digits than its factorization.

18240720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76019 (or 76013 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 18240720 is about 4270.9155927037. The cubic root of 18240720 is about 263.2372381664.

The spelling of 18240720 in words is "eighteen million, two hundred forty thousand, seven hundred twenty".