28515228 has 24 divisors (see below), whose sum is σ = 76040832. Its totient is φ = 8147184.

The previous prime is 28515217. The next prime is 28515247. The reversal of 28515228 is 82251582.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 169650 + ... + 169817.

It is an arithmetic number, because the mean of its divisors is an integer number (3168368).

Almost surely, 2^28515228 is an apocalyptic number.

28515228 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

28515228 is an abundant number, since it is smaller than the sum of its proper divisors (47525604).

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

28515228 is a wasteful number, since it uses less digits than its factorization.

28515228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 339481 (or 339479 counting only the distinct ones).

The product of its digits is 12800, while the sum is 33.

The square root of 28515228 is about 5339.9651684257. The cubic root of 28515228 is about 305.5101308023.

The spelling of 28515228 in words is "twenty-eight million, five hundred fifteen thousand, two hundred twenty-eight".