18009728 has 32 divisors (see below), whose sum is σ = 39143520. Its totient is φ = 8185600.

The previous prime is 18009683. The next prime is 18009763. The reversal of 18009728 is 82790081.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (32).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4988 + ... + 7803.

It is an arithmetic number, because the mean of its divisors is an integer number (1223235).

Almost surely, 2^18009728 is an apocalyptic number.

It is an amenable number.

18009728 is an abundant number, since it is smaller than the sum of its proper divisors (21133792).

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

18009728 is a wasteful number, since it uses less digits than its factorization.

18009728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12816 (or 12804 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 35.

The square root of 18009728 is about 4243.7869880568. The cubic root of 18009728 is about 262.1213430892.

The spelling of 18009728 in words is "eighteen million, nine thousand, seven hundred twenty-eight".