28121227 has 4 divisors (see below), whose sum is σ = 28202616. Its totient is φ = 28039840.

The previous prime is 28121209. The next prime is 28121239. The reversal of 28121227 is 72212182.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28121227 - 2⁷ = 28121099 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28121207) 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, 40174 + ... + 40867.

It is an arithmetic number, because the mean of its divisors is an integer number (7050654).

Almost surely, 2^28121227 is an apocalyptic number.

28121227 is a deficient number, since it is larger than the sum of its proper divisors (81389).

28121227 is an equidigital number, since it uses as much as digits as its factorization.

28121227 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81388.

The product of its digits is 896, while the sum is 25.

The square root of 28121227 is about 5302.9451251168. The cubic root of 28121227 is about 304.0965002679.

The spelling of 28121227 in words is "twenty-eight million, one hundred twenty-one thousand, two hundred twenty-seven".