28253309 has 16 divisors (see below), whose sum is σ = 33140736. Its totient is φ = 23587200.

The previous prime is 28253273. The next prime is 28253327. The reversal of 28253309 is 90335282.

It is not a de Polignac number, because 28253309 - 2⁸ = 28253053 is a prime.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28243309) 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, 53969 + ... + 54489.

It is an arithmetic number, because the mean of its divisors is an integer number (2071296).

Almost surely, 2^28253309 is an apocalyptic number.

It is an amenable number.

28253309 is a deficient number, since it is larger than the sum of its proper divisors (4887427).

28253309 is a wasteful number, since it uses less digits than its factorization.

28253309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 716.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 28253309 is about 5315.3841817878. The cubic root of 28253309 is about 304.5718582966.

The spelling of 28253309 in words is "twenty-eight million, two hundred fifty-three thousand, three hundred nine".