18311904 has 144 divisors (see below), whose sum is σ = 57696912. Its totient is φ = 5474304.

The previous prime is 18311893. The next prime is 18311947. The reversal of 18311904 is 40911381.

It is a tau number, because it is divible by the number of its divisors (144).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 250812 + ... + 250884.

It is an arithmetic number, because the mean of its divisors is an integer number (400673).

Almost surely, 2^18311904 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18311904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28848456).

18311904 is an abundant number, since it is smaller than the sum of its proper divisors (39385008).

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

18311904 is a wasteful number, since it uses less digits than its factorization.

18311904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169 (or 158 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 18311904 is about 4279.2410542058. The cubic root of 18311904 is about 263.5792194959.

The spelling of 18311904 in words is "eighteen million, three hundred eleven thousand, nine hundred four".