688705793689 has 3 divisors (see below), whose sum is σ = 688706623573. Its totient is φ = 688704963806.

The previous prime is 688705793683. The next prime is 688705793719. The reversal of 688705793689 is 986397507886.

The square root of 688705793689 is 829883.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 688705793689 - 2¹⁹ = 688705269401 is a prime.

It is a Smith number, since the sum of its digits (76) coincides with the sum of the digits of its prime factors.

It is a Duffinian 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 2 ways as a sum of consecutive naturals, for example, 414942 + ... + 1244824.

Almost surely, 2^688705793689 is an apocalyptic number.

688705793689 is the 829883-rd square number.

688705793689 is the 414942-nd centered octagonal number.

It is an amenable number.

688705793689 is a deficient number, since it is larger than the sum of its proper divisors (829884).

688705793689 is an frugal number, since it uses more digits than its factorization.

688705793689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1659766 (or 829883 counting only the distinct ones).

The product of its (nonzero) digits is 1097349120, while the sum is 76.

The spelling of 688705793689 in words is "six hundred eighty-eight billion, seven hundred five million, seven hundred ninety-three thousand, six hundred eighty-nine".