28249728 has 64 divisors (see below), whose sum is σ = 80824800. Its totient is φ = 8690688.

The previous prime is 28249723. The next prime is 28249729. The reversal of 28249728 is 82794282.

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

It is a self number, because there is not a number n which added to its sum of digits gives 28249728.

It is not an unprimeable number, because it can be changed into a prime (28249721) by changing a digit.

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, 2163 + ... + 7821.

Almost surely, 2^28249728 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 28249728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40412400).

28249728 is an abundant number, since it is smaller than the sum of its proper divisors (52575072).

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

28249728 is a wasteful number, since it uses less digits than its factorization.

28249728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5689 (or 5677 counting only the distinct ones).

The product of its digits is 129024, while the sum is 42.

The square root of 28249728 is about 5315.0473186981. The cubic root of 28249728 is about 304.5589899761.

The spelling of 28249728 in words is "twenty-eight million, two hundred forty-nine thousand, seven hundred twenty-eight".