28761728 has 32 divisors (see below), whose sum is σ = 58857060. Its totient is φ = 13989888.

The previous prime is 28761709. The next prime is 28761731. The reversal of 28761728 is 82716782.

It can be written as a sum of positive squares in 2 ways, for example, as 22963264 + 5798464 = 4792^2 + 2408^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1700 + ... + 7772.

Almost surely, 2^28761728 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 28761728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29428530).

28761728 is an abundant number, since it is smaller than the sum of its proper divisors (30095332).

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

28761728 is an equidigital number, since it uses as much as digits as its factorization.

28761728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6124 (or 6112 counting only the distinct ones).

The product of its digits is 75264, while the sum is 41.

The square root of 28761728 is about 5362.9961775112. The cubic root of 28761728 is about 306.3879340894.

Adding to 28761728 its sum of digits (41), we get a square (28761769 = 5363²).

The spelling of 28761728 in words is "twenty-eight million, seven hundred sixty-one thousand, seven hundred twenty-eight".