28328089 has 4 divisors (see below), whose sum is σ = 29019060. Its totient is φ = 27637120.

The previous prime is 28328081. The next prime is 28328117. The reversal of 28328089 is 98082382.

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 870489 + 27457600 = 933^2 + 5240^2 .

It is a cyclic number.

It is not a de Polignac number, because 28328089 - 2³ = 28328081 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28328081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 345424 + ... + 345505.

It is an arithmetic number, because the mean of its divisors is an integer number (7254765).

Almost surely, 2^28328089 is an apocalyptic number.

It is an amenable number.

28328089 is a deficient number, since it is larger than the sum of its proper divisors (690971).

28328089 is an equidigital number, since it uses as much as digits as its factorization.

28328089 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 690970.

The product of its (nonzero) digits is 55296, while the sum is 40.

The square root of 28328089 is about 5322.4138320878. The cubic root of 28328089 is about 304.8403320871.

The spelling of 28328089 in words is "twenty-eight million, three hundred twenty-eight thousand, eighty-nine".