18509904 has 80 divisors (see below), whose sum is σ = 60730240. Its totient is φ = 5287680.

The previous prime is 18509903. The next prime is 18509929. The reversal of 18509904 is 40990581.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18509903) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37 + ... + 6084.

It is an arithmetic number, because the mean of its divisors is an integer number (759128).

Almost surely, 2^18509904 is an apocalyptic number.

18509904 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 18509904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30365120).

18509904 is an abundant number, since it is smaller than the sum of its proper divisors (42220336).

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

18509904 is a wasteful number, since it uses less digits than its factorization.

18509904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6145 (or 6133 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 18509904 is about 4302.3137960869. The cubic root of 18509904 is about 264.5258115445.

The spelling of 18509904 in words is "eighteen million, five hundred nine thousand, nine hundred four".