18439728 has 40 divisors (see below), whose sum is σ = 50145600. Its totient is φ = 5822784.

The previous prime is 18439717. The next prime is 18439739. The reversal of 18439728 is 82793481.

It is an interprime number because it is at equal distance from previous prime (18439717) and next prime (18439739).

It is a self number, because there is not a number n which added to its sum of digits gives 18439728.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9198 + ... + 11021.

It is an arithmetic number, because the mean of its divisors is an integer number (1253640).

Almost surely, 2^18439728 is an apocalyptic number.

It is an amenable number.

18439728 is an abundant number, since it is smaller than the sum of its proper divisors (31705872).

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

18439728 is a wasteful number, since it uses less digits than its factorization.

18439728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20249 (or 20243 counting only the distinct ones).

The product of its digits is 96768, while the sum is 42.

The square root of 18439728 is about 4294.1504398426. The cubic root of 18439728 is about 264.1910921344.

The spelling of 18439728 in words is "eighteen million, four hundred thirty-nine thousand, seven hundred twenty-eight".