28721568 has 48 divisors (see below), whose sum is σ = 79833600. Its totient is φ = 9010176.

The previous prime is 28721557. The next prime is 28721573. The reversal of 28721568 is 86512782.

It is a tau number, because it is divible by the number of its divisors (48).

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, 7168 + ... + 10431.

It is an arithmetic number, because the mean of its divisors is an integer number (1663200).

Almost surely, 2^28721568 is an apocalyptic number.

It is an amenable number.

28721568 is an abundant number, since it is smaller than the sum of its proper divisors (51112032).

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

28721568 is a wasteful number, since it uses less digits than its factorization.

28721568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17629 (or 17621 counting only the distinct ones).

The product of its digits is 53760, while the sum is 39.

The square root of 28721568 is about 5359.2506938937. The cubic root of 28721568 is about 306.2452645110.

The spelling of 28721568 in words is "twenty-eight million, seven hundred twenty-one thousand, five hundred sixty-eight".