28931728 has 20 divisors (see below), whose sum is σ = 64063360. Its totient is φ = 12399264.

The previous prime is 28931681. The next prime is 28931759. The reversal of 28931728 is 82713982.

It is a congruent number.

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, 129048 + ... + 129271.

It is an arithmetic number, because the mean of its divisors is an integer number (3203168).

Almost surely, 2^28931728 is an apocalyptic number.

28931728 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

28931728 is an abundant number, since it is smaller than the sum of its proper divisors (35131632).

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

28931728 is a wasteful number, since it uses less digits than its factorization.

28931728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258334 (or 258328 counting only the distinct ones).

The product of its digits is 48384, while the sum is 40.

The square root of 28931728 is about 5378.8221759043. The cubic root of 28931728 is about 306.9903974758.

The spelling of 28931728 in words is "twenty-eight million, nine hundred thirty-one thousand, seven hundred twenty-eight".