28057728 has 64 divisors (see below), whose sum is σ = 76965120. Its totient is φ = 9047040.

The previous prime is 28057721. The next prime is 28057739. The reversal of 28057728 is 82775082.

It is a tau number, because it is divible by the number of its divisors (64).

It is a super-2 number, since 2×28057728² = 1574472201043968, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28057721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10726 + ... + 13082.

It is an arithmetic number, because the mean of its divisors is an integer number (1202580).

Almost surely, 2^28057728 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 28057728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38482560).

28057728 is an abundant number, since it is smaller than the sum of its proper divisors (48907392).

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

28057728 is a wasteful number, since it uses less digits than its factorization.

28057728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2405 (or 2393 counting only the distinct ones).

The product of its (nonzero) digits is 62720, while the sum is 39.

The square root of 28057728 is about 5296.9545967471. The cubic root of 28057728 is about 303.8674398968.

The spelling of 28057728 in words is "twenty-eight million, fifty-seven thousand, seven hundred twenty-eight".