18243904 has 56 divisors (see below), whose sum is σ = 41786048. Its totient is φ = 7741440.

The previous prime is 18243881. The next prime is 18243913. The reversal of 18243904 is 40934281.

It is a tau number, because it is divible by the number of its divisors (56).

It is a super-2 number, since 2×18243904² = 665680066322432, which contains 22 as substring.

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, 86359 + ... + 86569.

Almost surely, 2^18243904 is an apocalyptic number.

18243904 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 18243904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20893024).

18243904 is an abundant number, since it is smaller than the sum of its proper divisors (23542144).

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

18243904 is a wasteful number, since it uses less digits than its factorization.

18243904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 423 (or 413 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 18243904 is about 4271.2883302348. The cubic root of 18243904 is about 263.2525536913.

The spelling of 18243904 in words is "eighteen million, two hundred forty-three thousand, nine hundred four".