28217856 has 40 divisors (see below), whose sum is σ = 75178224. Its totient is φ = 9405440.

The previous prime is 28217851. The next prime is 28217863. The reversal of 28217856 is 65871282.

It is not an unprimeable number, because it can be changed into a prime (28217851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7650 + ... + 10721.

Almost surely, 2^28217856 is an apocalyptic number.

It is an amenable number.

28217856 is an abundant number, since it is smaller than the sum of its proper divisors (46960368).

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

28217856 is an equidigital number, since it uses as much as digits as its factorization.

28217856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18392 (or 18376 counting only the distinct ones).

The product of its digits is 53760, while the sum is 39.

The square root of 28217856 is about 5312.0481925525. The cubic root of 28217856 is about 304.4444100299. Note that the first 4 decimals are identical.

The spelling of 28217856 in words is "twenty-eight million, two hundred seventeen thousand, eight hundred fifty-six".