28915309 has 2 divisors, whose sum is σ = 28915310. Its totient is φ = 28915308.

The previous prime is 28915261. The next prime is 28915319. The reversal of 28915309 is 90351982.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28590409 + 324900 = 5347^2 + 570^2 .

It is a cyclic number.

It is not a de Polignac number, because 28915309 - 2¹³ = 28907117 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28915319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14457654 + 14457655.

It is an arithmetic number, because the mean of its divisors is an integer number (14457655).

Almost surely, 2^28915309 is an apocalyptic number.

It is an amenable number.

28915309 is a deficient number, since it is larger than the sum of its proper divisors (1).

28915309 is an equidigital number, since it uses as much as digits as its factorization.

28915309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 19440, while the sum is 37.

The square root of 28915309 is about 5377.2956957936. The cubic root of 28915309 is about 306.9323132721.

The spelling of 28915309 in words is "twenty-eight million, nine hundred fifteen thousand, three hundred nine".