28129775 has 12 divisors (see below), whose sum is σ = 34947912. Its totient is φ = 22460640.

The previous prime is 28129771. The next prime is 28129789. The reversal of 28129775 is 57792182.

It is not a de Polignac number, because 28129775 - 2² = 28129771 is a prime.

It is a hoax number, since the sum of its digits (41) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28129771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21284 + ... + 22566.

It is an arithmetic number, because the mean of its divisors is an integer number (2912326).

Almost surely, 2^28129775 is an apocalyptic number.

28129775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

28129775 is a deficient number, since it is larger than the sum of its proper divisors (6818137).

28129775 is a wasteful number, since it uses less digits than its factorization.

28129775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2170 (or 2165 counting only the distinct ones).

The product of its digits is 70560, while the sum is 41.

The square root of 28129775 is about 5303.7510311100. The cubic root of 28129775 is about 304.1273091838.

The spelling of 28129775 in words is "twenty-eight million, one hundred twenty-nine thousand, seven hundred seventy-five".