28003665 has 16 divisors (see below), whose sum is σ = 44900928. Its totient is φ = 14903616.

The previous prime is 28003649. The next prime is 28003667. The reversal of 28003665 is 56630082.

It is not a de Polignac number, because 28003665 - 2⁴ = 28003649 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28003667) 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 15 ways as a sum of consecutive naturals, for example, 6499 + ... + 9911.

It is an arithmetic number, because the mean of its divisors is an integer number (2806308).

Almost surely, 2^28003665 is an apocalyptic number.

It is an amenable number.

28003665 is a deficient number, since it is larger than the sum of its proper divisors (16897263).

28003665 is a wasteful number, since it uses less digits than its factorization.

28003665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3968.

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 28003665 is about 5291.8489207459. The cubic root of 28003665 is about 303.6721455364.

The spelling of 28003665 in words is "twenty-eight million, three thousand, six hundred sixty-five".