28913309 has 2 divisors, whose sum is σ = 28913310. Its totient is φ = 28913308.

The previous prime is 28913293. The next prime is 28913327. The reversal of 28913309 is 90331982.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 24226084 + 4687225 = 4922^2 + 2165^2 .

It is a cyclic number.

It is not a de Polignac number, because 28913309 - 2⁴ = 28913293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28913399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14456654 + 14456655.

It is an arithmetic number, because the mean of its divisors is an integer number (14456655).

Almost surely, 2^28913309 is an apocalyptic number.

It is an amenable number.

28913309 is a deficient number, since it is larger than the sum of its proper divisors (1).

28913309 is an equidigital number, since it uses as much as digits as its factorization.

28913309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 28913309 is about 5377.1097254938. The cubic root of 28913309 is about 306.9252365274.

The spelling of 28913309 in words is "twenty-eight million, nine hundred thirteen thousand, three hundred nine".