688684 has 6 divisors (see below), whose sum is σ = 1205204. Its totient is φ = 344340.

The previous prime is 688679. The next prime is 688697. The reversal of 688684 is 486886.

It is a happy number.

It is an unprimeable 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 as a sum of consecutive naturals, namely, 86082 + ... + 86089.

2⁶⁸⁸⁶⁸⁴ is an apocalyptic number.

It is an amenable number.

688684 is a deficient number, since it is larger than the sum of its proper divisors (516520).

688684 is a wasteful number, since it uses less digits than its factorization.

688684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172175 (or 172173 counting only the distinct ones).

The product of its digits is 73728, while the sum is 40.

The square root of 688684 is about 829.8698693169. The cubic root of 688684 is about 88.3093451733.

The spelling of 688684 in words is "six hundred eighty-eight thousand, six hundred eighty-four".