28090809 has 6 divisors (see below), whose sum is σ = 40575626. Its totient is φ = 18727200.

The previous prime is 28090771. The next prime is 28090823. The reversal of 28090809 is 90809082.

It can be written as a sum of positive squares in only one way, i.e., 27405225 + 685584 = 5235^2 + 828^2 .

It is not a de Polignac number, because 28090809 - 2¹³ = 28082617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28090859) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1560592 + ... + 1560609.

Almost surely, 2^28090809 is an apocalyptic number.

It is an amenable number.

28090809 is a deficient number, since it is larger than the sum of its proper divisors (12484817).

28090809 is a wasteful number, since it uses less digits than its factorization.

28090809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3121207 (or 3121204 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 28090809 is about 5300.0763202052. The cubic root of 28090809 is about 303.9868162854.

The spelling of 28090809 in words is "twenty-eight million, ninety thousand, eight hundred nine".