688391568 has 40 divisors (see below), whose sum is σ = 1975940000. Its totient is φ = 229463712.

The previous prime is 688391551. The next prime is 688391579. The reversal of 688391568 is 865193886.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 796318 + ... + 797181.

It is an arithmetic number, because the mean of its divisors is an integer number (49398500).

Almost surely, 2^688391568 is an apocalyptic number.

It is an amenable number.

688391568 is an abundant number, since it is smaller than the sum of its proper divisors (1287548432).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

688391568 is a wasteful number, since it uses less digits than its factorization.

688391568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1593516 (or 1593504 counting only the distinct ones).

The product of its digits is 2488320, while the sum is 54.

The square root of 688391568 is about 26237.2172304915. The cubic root of 688391568 is about 882.9684397076.

It can be divided in two parts, 68839 and 1568, that added together give a palindrome (70407).

The spelling of 688391568 in words is "six hundred eighty-eight million, three hundred ninety-one thousand, five hundred sixty-eight".