18131904 has 112 divisors (see below), whose sum is σ = 60960000. Its totient is φ = 5177088.

The previous prime is 18131879. The next prime is 18131921. The reversal of 18131904 is 40913181.

It is a tau number, because it is divible by the number of its divisors (112).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

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, 11347 + ... + 12845.

Almost surely, 2^18131904 is an apocalyptic number.

18131904 is a gapful number since it is divisible by the number (14) 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 18131904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30480000).

18131904 is an abundant number, since it is smaller than the sum of its proper divisors (42828096).

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

18131904 is a wasteful number, since it uses less digits than its factorization.

18131904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1527 (or 1511 counting only the distinct ones).

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

The square root of 18131904 is about 4258.1573479617. The cubic root of 18131904 is about 262.7127418236.

The spelling of 18131904 in words is "eighteen million, one hundred thirty-one thousand, nine hundred four".