28817856639 has 96 divisors (see below), whose sum is σ = 49646198784. Its totient is φ = 15878903040.

The previous prime is 28817856623. The next prime is 28817856737. The reversal of 28817856639 is 93665871882.

28817856639 is a `hidden beast` number, since 28 + 8 + 17 + 8 + 566 + 39 = 666.

It is not a de Polignac number, because 28817856639 - 2⁴ = 28817856623 is a prime.

It is a super-2 number, since 2×28817856639² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28817856139) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 25660932 + ... + 25662054.

It is an arithmetic number, because the mean of its divisors is an integer number (517147904).

Almost surely, 2^28817856639 is an apocalyptic number.

28817856639 is a deficient number, since it is larger than the sum of its proper divisors (20828342145).

28817856639 is a wasteful number, since it uses less digits than its factorization.

28817856639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1437 (or 1434 counting only the distinct ones).

The product of its digits is 34836480, while the sum is 63.

The spelling of 28817856639 in words is "twenty-eight billion, eight hundred seventeen million, eight hundred fifty-six thousand, six hundred thirty-nine".