28531308688 has 20 divisors (see below), whose sum is σ = 55286287468. Its totient is φ = 14263879680.

The previous prime is 28531308671. The next prime is 28531308719. The reversal of 28531308688 is 88680313582.

It can be written as a sum of positive squares in 2 ways, for example, as 18858979584 + 9672329104 = 137328^2 + 98348^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26908 + ... + 240388.

Almost surely, 2^28531308688 is an apocalyptic number.

It is an amenable number.

28531308688 is a deficient number, since it is larger than the sum of its proper divisors (26754978780).

28531308688 is a wasteful number, since it uses less digits than its factorization.

28531308688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221842 (or 221836 counting only the distinct ones).

The product of its (nonzero) digits is 2211840, while the sum is 52.

The spelling of 28531308688 in words is "twenty-eight billion, five hundred thirty-one million, three hundred eight thousand, six hundred eighty-eight".