18307872 has 72 divisors (see below), whose sum is σ = 56805840. Its totient is φ = 5546880.

The previous prime is 18307831. The next prime is 18307907. The reversal of 18307872 is 27870381.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an alternating number because its digits alternate between odd and even.

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 11 ways as a sum of consecutive naturals, for example, 279 + ... + 6057.

It is an arithmetic number, because the mean of its divisors is an integer number (788970).

Almost surely, 2^18307872 is an apocalyptic number.

18307872 is a gapful number since it is divisible by the number (12) 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 18307872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28402920).

18307872 is an abundant number, since it is smaller than the sum of its proper divisors (38497968).

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

18307872 is a wasteful number, since it uses less digits than its factorization.

18307872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5806 (or 5795 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The square root of 18307872 is about 4278.7699166933. The cubic root of 18307872 is about 263.5598727107.

The spelling of 18307872 in words is "eighteen million, three hundred seven thousand, eight hundred seventy-two".