28452221 has 4 divisors (see below), whose sum is σ = 32516832. Its totient is φ = 24387612.

The previous prime is 28452217. The next prime is 28452227. The reversal of 28452221 is 12225482.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 28452221 - 2² = 28452217 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28452227) 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, 2032295 + ... + 2032308.

It is an arithmetic number, because the mean of its divisors is an integer number (8129208).

Almost surely, 2^28452221 is an apocalyptic number.

It is an amenable number.

28452221 is a deficient number, since it is larger than the sum of its proper divisors (4064611).

28452221 is an equidigital number, since it uses as much as digits as its factorization.

28452221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4064610.

The product of its digits is 2560, while the sum is 26.

The square root of 28452221 is about 5334.0623355938. The cubic root of 28452221 is about 305.2849473562.

The spelling of 28452221 in words is "twenty-eight million, four hundred fifty-two thousand, two hundred twenty-one".