28113309 has 30 divisors (see below), whose sum is σ = 47409726. Its totient is φ = 16052400.

The previous prime is 28113307. The next prime is 28113313. The reversal of 28113309 is 90331182.

It can be written as a sum of positive squares in only one way, i.e., 14607684 + 13505625 = 3822^2 + 3675^2 .

It is not a de Polignac number, because 28113309 - 2¹ = 28113307 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28113307) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 20959 + ... + 22259.

Almost surely, 2^28113309 is an apocalyptic number.

It is an amenable number.

28113309 is a deficient number, since it is larger than the sum of its proper divisors (19296417).

28113309 is an equidigital number, since it uses as much as digits as its factorization.

28113309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1335 (or 1311 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 28113309 is about 5302.1985062802. The cubic root of 28113309 is about 304.0679564433.

The spelling of 28113309 in words is "twenty-eight million, one hundred thirteen thousand, three hundred nine".