28388628 has 36 divisors (see below), whose sum is σ = 71928948. Its totient is φ = 9440640.

The previous prime is 28388627. The next prime is 28388629. The reversal of 28388628 is 82688382.

It is an interprime number because it is at equal distance from previous prime (28388627) and next prime (28388629).

It can be written as a sum of positive squares in 2 ways, for example, as 18766224 + 9622404 = 4332^2 + 3102^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28388621) 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 11 ways as a sum of consecutive naturals, for example, 23200 + ... + 24392.

Almost surely, 2^28388628 is an apocalyptic number.

It is an amenable number.

28388628 is an abundant number, since it is smaller than the sum of its proper divisors (43540320).

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

28388628 is a wasteful number, since it uses less digits than its factorization.

28388628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1864 (or 1859 counting only the distinct ones).

The product of its digits is 294912, while the sum is 45.

The square root of 28388628 is about 5328.0979720722. The cubic root of 28388628 is about 305.0573322305.

The spelling of 28388628 in words is "twenty-eight million, three hundred eighty-eight thousand, six hundred twenty-eight".