28318809 has 4 divisors (see below), whose sum is σ = 37758416. Its totient is φ = 18879204.

The previous prime is 28318799. The next prime is 28318813. The reversal of 28318809 is 90881382.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 28318809 - 2⁴ = 28318793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28318009) 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 in 3 ways as a sum of consecutive naturals, for example, 4719799 + ... + 4719804.

It is an arithmetic number, because the mean of its divisors is an integer number (9439604).

Almost surely, 2^28318809 is an apocalyptic number.

It is an amenable number.

28318809 is a deficient number, since it is larger than the sum of its proper divisors (9439607).

28318809 is an equidigital number, since it uses as much as digits as its factorization.

28318809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9439606.

The product of its (nonzero) digits is 27648, while the sum is 39.

The square root of 28318809 is about 5321.5419757811. The cubic root of 28318809 is about 304.8070408987.

The spelling of 28318809 in words is "twenty-eight million, three hundred eighteen thousand, eight hundred nine".