28320728 has 32 divisors (see below), whose sum is σ = 55836000. Its totient is φ = 13440768.

The previous prime is 28320713. The next prime is 28320731. The reversal of 28320728 is 82702382.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 28320694 and 28320703.

It is a congruent number.

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, 26900 + ... + 27932.

It is an arithmetic number, because the mean of its divisors is an integer number (1744875).

Almost surely, 2^28320728 is an apocalyptic number.

It is an amenable number.

28320728 is a deficient number, since it is larger than the sum of its proper divisors (27515272).

28320728 is a wasteful number, since it uses less digits than its factorization.

28320728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1211 (or 1207 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 32.

The square root of 28320728 is about 5321.7222776090. The cubic root of 28320728 is about 304.8139257398.

The spelling of 28320728 in words is "twenty-eight million, three hundred twenty thousand, seven hundred twenty-eight".