28398005 has 4 divisors (see below), whose sum is σ = 34077612. Its totient is φ = 22718400.

The previous prime is 28397987. The next prime is 28398037. The reversal of 28398005 is 50089382.

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 20857489 + 7540516 = 4567^2 + 2746^2 .

It is not a de Polignac number, because 28398005 - 2¹⁰ = 28396981 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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, 2839796 + ... + 2839805.

It is an arithmetic number, because the mean of its divisors is an integer number (8519403).

Almost surely, 2^28398005 is an apocalyptic number.

It is an amenable number.

28398005 is a deficient number, since it is larger than the sum of its proper divisors (5679607).

28398005 is an equidigital number, since it uses as much as digits as its factorization.

28398005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5679606.

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 28398005 is about 5328.9778569628. The cubic root of 28398005 is about 305.0909161913.

The spelling of 28398005 in words is "twenty-eight million, three hundred ninety-eight thousand, five".