28187173729 has 24 divisors (see below), whose sum is σ = 33446286720. Its totient is φ = 23596568160.

The previous prime is 28187173717. The next prime is 28187173733. The reversal of 28187173729 is 92737178182.

It is a de Polignac number, because none of the positive numbers 2^k-28187173729 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28187173729.

It is not an unprimeable number, because it can be changed into a prime (28187173769) 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 23 ways as a sum of consecutive naturals, for example, 637704 + ... + 680470.

It is an arithmetic number, because the mean of its divisors is an integer number (1393595280).

Almost surely, 2^28187173729 is an apocalyptic number.

It is an amenable number.

28187173729 is a deficient number, since it is larger than the sum of its proper divisors (5259112991).

28187173729 is a wasteful number, since it uses less digits than its factorization.

28187173729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43221 (or 43210 counting only the distinct ones).

The product of its digits is 2370816, while the sum is 55.

The spelling of 28187173729 in words is "twenty-eight billion, one hundred eighty-seven million, one hundred seventy-three thousand, seven hundred twenty-nine".