28115809 has 2 divisors, whose sum is σ = 28115810. Its totient is φ = 28115808.

The previous prime is 28115797. The next prime is 28115827. The reversal of 28115809 is 90851182.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28058209 + 57600 = 5297^2 + 240^2 .

It is a cyclic number.

It is not a de Polignac number, because 28115809 - 2¹³ = 28107617 is a prime.

It is not a weakly prime, because it can be changed into another prime (28115209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14057904 + 14057905.

It is an arithmetic number, because the mean of its divisors is an integer number (14057905).

Almost surely, 2^28115809 is an apocalyptic number.

It is an amenable number.

28115809 is a deficient number, since it is larger than the sum of its proper divisors (1).

28115809 is an equidigital number, since it uses as much as digits as its factorization.

28115809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5760, while the sum is 34.

The square root of 28115809 is about 5302.4342523034. The cubic root of 28115809 is about 304.0769693437.

The spelling of 28115809 in words is "twenty-eight million, one hundred fifteen thousand, eight hundred nine".