688688 has 80 divisors (see below), whose sum is σ = 1833216. Its totient is φ = 241920.

The previous prime is 688679. The next prime is 688697. The reversal of 688688 is 886886.

It is an interprime number because it is at equal distance from previous prime (688679) and next prime (688697).

It is a super-2 number, since 2×688688² = 948582322688, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 688688.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15995 + ... + 16037.

2⁶⁸⁸⁶⁸⁸ 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 688688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (916608).

688688 is an abundant number, since it is smaller than the sum of its proper divisors (1144528).

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

688688 is a wasteful number, since it uses less digits than its factorization.

688688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82 (or 76 counting only the distinct ones).

The product of its digits is 147456, while the sum is 44.

The square root of 688688 is about 829.8722793298. The cubic root of 688688 is about 88.3095161451.

The spelling of 688688 in words is "six hundred eighty-eight thousand, six hundred eighty-eight".