28905865 has 16 divisors (see below), whose sum is σ = 37149840. Its totient is φ = 21514240.

The previous prime is 28905853. The next prime is 28905907. The reversal of 28905865 is 56850982.

It can be written as a sum of positive squares in 8 ways, for example, as 571536 + 28334329 = 756^2 + 5323^2 .

It is not a de Polignac number, because 28905865 - 2⁹ = 28905353 is a prime.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 5655 + ... + 9475.

It is an arithmetic number, because the mean of its divisors is an integer number (2321865).

Almost surely, 2^28905865 is an apocalyptic number.

It is an amenable number.

28905865 is a deficient number, since it is larger than the sum of its proper divisors (8243975).

28905865 is a wasteful number, since it uses less digits than its factorization.

28905865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3932.

The product of its (nonzero) digits is 172800, while the sum is 43.

The square root of 28905865 is about 5376.4174875097. The cubic root of 28905865 is about 306.8988940154.

The spelling of 28905865 in words is "twenty-eight million, nine hundred five thousand, eight hundred sixty-five".