28756728 has 384 divisors, whose sum is σ = 114912000. Its totient is φ = 6531840.

The previous prime is 28756699. The next prime is 28756729. The reversal of 28756728 is 82765782.

28756728 is a `hidden beast` number, since 2 + 87 + 567 + 2 + 8 = 666.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28756729) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1513503 + ... + 1513521.

It is an arithmetic number, because the mean of its divisors is an integer number (299250).

Almost surely, 2^28756728 is an apocalyptic number.

28756728 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28756728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (57456000).

28756728 is an abundant number, since it is smaller than the sum of its proper divisors (86155272).

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

28756728 is a wasteful number, since it uses less digits than its factorization.

28756728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72 (or 55 counting only the distinct ones).

The product of its digits is 376320, while the sum is 45.

The square root of 28756728 is about 5362.5299999161. The cubic root of 28756728 is about 306.3701786836.

The spelling of 28756728 in words is "twenty-eight million, seven hundred fifty-six thousand, seven hundred twenty-eight".