18123720 has 64 divisors (see below), whose sum is σ = 57240000. Its totient is φ = 4578048.

The previous prime is 18123713. The next prime is 18123733. The reversal of 18123720 is 2732181.

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

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1695 + ... + 6254.

It is an arithmetic number, because the mean of its divisors is an integer number (894375).

Almost surely, 2^18123720 is an apocalyptic number.

18123720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18123720 is an abundant number, since it is smaller than the sum of its proper divisors (39116280).

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

18123720 is a wasteful number, since it uses less digits than its factorization.

18123720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7982 (or 7978 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 18123720 is about 4257.1962604512. The cubic root of 18123720 is about 262.6732099458.

The spelling of 18123720 in words is "eighteen million, one hundred twenty-three thousand, seven hundred twenty".