28531308689 has 4 divisors (see below), whose sum is σ = 30726024756. Its totient is φ = 26336592624.

The previous prime is 28531308671. The next prime is 28531308719. The reversal of 28531308689 is 98680313582.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7703046289 + 20828262400 = 87767^2 + 144320^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28531308689 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28531308689.

It is not an unprimeable number, because it can be changed into a prime (28531308889) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1097358014 + ... + 1097358039.

It is an arithmetic number, because the mean of its divisors is an integer number (7681506189).

Almost surely, 2^28531308689 is an apocalyptic number.

It is an amenable number.

28531308689 is a deficient number, since it is larger than the sum of its proper divisors (2194716067).

28531308689 is a wasteful number, since it uses less digits than its factorization.

28531308689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2194716066.

The product of its (nonzero) digits is 2488320, while the sum is 53.

The spelling of 28531308689 in words is "twenty-eight billion, five hundred thirty-one million, three hundred eight thousand, six hundred eighty-nine".