688764 has 12 divisors (see below), whose sum is σ = 1607144. Its totient is φ = 229584.

The previous prime is 688763. The next prime is 688777. The reversal of 688764 is 467886.

It is a tau number, because it is divible by the number of its divisors (12).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688763) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28687 + ... + 28710.

2⁶⁸⁸⁷⁶⁴ is an apocalyptic number.

It is an amenable number.

688764 is an abundant number, since it is smaller than the sum of its proper divisors (918380).

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

688764 is a wasteful number, since it uses less digits than its factorization.

688764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57404 (or 57402 counting only the distinct ones).

The product of its digits is 64512, while the sum is 39.

The square root of 688764 is about 829.9180682453. The cubic root of 688764 is about 88.3127644842.

The spelling of 688764 in words is "six hundred eighty-eight thousand, seven hundred sixty-four".