28643865 has 16 divisors (see below), whose sum is σ = 46125888. Its totient is φ = 15178176.

The previous prime is 28643863. The next prime is 28643873. The reversal of 28643865 is 56834682.

It is not a de Polignac number, because 28643865 - 2¹ = 28643863 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28643863) by changing a digit.

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, 3727 + ... + 8436.

It is an arithmetic number, because the mean of its divisors is an integer number (2882868).

Almost surely, 2^28643865 is an apocalyptic number.

It is an amenable number.

28643865 is a deficient number, since it is larger than the sum of its proper divisors (17482023).

28643865 is a wasteful number, since it uses less digits than its factorization.

28643865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12328.

The product of its digits is 276480, while the sum is 42.

The square root of 28643865 is about 5351.9963565010. The cubic root of 28643865 is about 305.9688442798.

The spelling of 28643865 in words is "twenty-eight million, six hundred forty-three thousand, eight hundred sixty-five".