18305728 has 56 divisors (see below), whose sum is σ = 42976800. Its totient is φ = 7569408.

The previous prime is 18305711. The next prime is 18305731. The reversal of 18305728 is 82750381.

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

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 18305693 and 18305702.

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, 12288 + ... + 13696.

Almost surely, 2^18305728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18305728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21488400).

18305728 is an abundant number, since it is smaller than the sum of its proper divisors (24671072).

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

18305728 is a wasteful number, since it uses less digits than its factorization.

18305728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1457 (or 1447 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 34.

The square root of 18305728 is about 4278.5193700625. The cubic root of 18305728 is about 263.5495839776.

The spelling of 18305728 in words is "eighteen million, three hundred five thousand, seven hundred twenty-eight".