688728 has 16 divisors (see below), whose sum is σ = 1721880. Its totient is φ = 229568.

The previous prime is 688717. The next prime is 688729. The reversal of 688728 is 827886.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688729) by changing a digit.

688728 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14325 + ... + 14372.

2⁶⁸⁸⁷²⁸ is an apocalyptic number.

It is an amenable number.

688728 is an abundant number, since it is smaller than the sum of its proper divisors (1033152).

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

688728 is a wasteful number, since it uses less digits than its factorization.

688728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28706 (or 28702 counting only the distinct ones).

The product of its digits is 43008, while the sum is 39.

The square root of 688728 is about 829.8963790739. The cubic root of 688728 is about 88.3112258271.

The spelling of 688728 in words is "six hundred eighty-eight thousand, seven hundred twenty-eight".