28279321 has 16 divisors (see below), whose sum is σ = 34128000. Its totient is φ = 23395344.

The previous prime is 28279309. The next prime is 28279333. The reversal of 28279321 is 12397282.

It is an interprime number because it is at equal distance from previous prime (28279309) and next prime (28279333).

It is not a de Polignac number, because 28279321 - 2¹⁷ = 28148249 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28279301) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8526 + ... + 11368.

It is an arithmetic number, because the mean of its divisors is an integer number (2133000).

Almost surely, 2^28279321 is an apocalyptic number.

It is an amenable number.

28279321 is a deficient number, since it is larger than the sum of its proper divisors (5848679).

28279321 is an equidigital number, since it uses as much as digits as its factorization.

28279321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2893 (or 2879 counting only the distinct ones).

The product of its digits is 12096, while the sum is 34.

The square root of 28279321 is about 5317.8304786821. The cubic root of 28279321 is about 304.6652997772.

The spelling of 28279321 in words is "twenty-eight million, two hundred seventy-nine thousand, three hundred twenty-one".