28661728 has 96 divisors (see below), whose sum is σ = 65318400. Its totient is φ = 12294144.

The previous prime is 28661713. The next prime is 28661783. The reversal of 28661728 is 82716682.

Its product of digits (64512) is a multiple of the sum of its prime divisors (144).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 485763 + ... + 485821.

It is an arithmetic number, because the mean of its divisors is an integer number (680400).

Almost surely, 2^28661728 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 28661728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32659200).

28661728 is an abundant number, since it is smaller than the sum of its proper divisors (36656672).

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

28661728 is a wasteful number, since it uses less digits than its factorization.

28661728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152 (or 144 counting only the distinct ones).

The product of its digits is 64512, while the sum is 40.

The square root of 28661728 is about 5353.6649129358. The cubic root of 28661728 is about 306.0324342285.

The spelling of 28661728 in words is "twenty-eight million, six hundred sixty-one thousand, seven hundred twenty-eight".