28968809 has 4 divisors (see below), whose sum is σ = 29365716. Its totient is φ = 28571904.

The previous prime is 28968791. The next prime is 28968829. The reversal of 28968809 is 90886982.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8970025 + 19998784 = 2995^2 + 4472^2 .

It is a cyclic number.

It is not a de Polignac number, because 28968809 - 2²⁴ = 12191593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28968829) 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 3 ways as a sum of consecutive naturals, for example, 198344 + ... + 198489.

It is an arithmetic number, because the mean of its divisors is an integer number (7341429).

Almost surely, 2^28968809 is an apocalyptic number.

It is an amenable number.

28968809 is a deficient number, since it is larger than the sum of its proper divisors (396907).

28968809 is an equidigital number, since it uses as much as digits as its factorization.

28968809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 396906.

The product of its (nonzero) digits is 497664, while the sum is 50.

The square root of 28968809 is about 5382.2680163663. The cubic root of 28968809 is about 307.1214951998.

The spelling of 28968809 in words is "twenty-eight million, nine hundred sixty-eight thousand, eight hundred nine".