28129865 has 16 divisors (see below), whose sum is σ = 35143680. Its totient is φ = 21591360.

The previous prime is 28129853. The next prime is 28129867. The reversal of 28129865 is 56892182.

It is a de Polignac number, because none of the positive numbers 2^k-28129865 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28129867) 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, 18971 + ... + 20399.

It is an arithmetic number, because the mean of its divisors is an integer number (2196480).

Almost surely, 2^28129865 is an apocalyptic number.

It is an amenable number.

28129865 is a deficient number, since it is larger than the sum of its proper divisors (7013815).

28129865 is a wasteful number, since it uses less digits than its factorization.

28129865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1592.

The product of its digits is 69120, while the sum is 41.

The square root of 28129865 is about 5303.7595156643. The cubic root of 28129865 is about 304.1276335308.

The spelling of 28129865 in words is "twenty-eight million, one hundred twenty-nine thousand, eight hundred sixty-five".