688705793688 has 128 divisors (see below), whose sum is σ = 1977550848000. Its totient is φ = 197674081920.

The previous prime is 688705793683. The next prime is 688705793719. The reversal of 688705793688 is 886397507886.

It is a Cunningham number, because it is equal to 829883²-1.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688705793683) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 31524673 + ... + 31546511.

It is an arithmetic number, because the mean of its divisors is an integer number (15449616000).

Almost surely, 2^688705793688 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 688705793688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (988775424000).

688705793688 is an abundant number, since it is smaller than the sum of its proper divisors (1288845054312).

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

688705793688 is a wasteful number, since it uses less digits than its factorization.

688705793688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28165 (or 28161 counting only the distinct ones).

The product of its (nonzero) digits is 975421440, while the sum is 75.

The spelling of 688705793688 in words is "six hundred eighty-eight billion, seven hundred five million, seven hundred ninety-three thousand, six hundred eighty-eight".