28221275 has 12 divisors (see below), whose sum is σ = 37053432. Its totient is φ = 21248640.

The previous prime is 28221229. The next prime is 28221283. The reversal of 28221275 is 57212282.

It is not a de Polignac number, because 28221275 - 2⁶ = 28221211 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 32777 + ... + 33626.

It is an arithmetic number, because the mean of its divisors is an integer number (3087786).

Almost surely, 2^28221275 is an apocalyptic number.

28221275 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

28221275 is a deficient number, since it is larger than the sum of its proper divisors (8832157).

28221275 is a wasteful number, since it uses less digits than its factorization.

28221275 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66430 (or 66425 counting only the distinct ones).

The product of its digits is 4480, while the sum is 29.

The square root of 28221275 is about 5312.3699984094. The cubic root of 28221275 is about 304.4567054762.

The spelling of 28221275 in words is "twenty-eight million, two hundred twenty-one thousand, two hundred seventy-five".