687684 has 24 divisors (see below), whose sum is σ = 1699488. Its totient is φ = 215680.

The previous prime is 687683. The next prime is 687691. The reversal of 687684 is 486786.

687684 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687683) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1482 + ... + 1889.

It is an arithmetic number, because the mean of its divisors is an integer number (70812).

2⁶⁸⁷⁶⁸⁴ is an apocalyptic number.

It is an amenable number.

687684 is an abundant number, since it is smaller than the sum of its proper divisors (1011804).

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

687684 is a wasteful number, since it uses less digits than its factorization.

687684 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3395 (or 3393 counting only the distinct ones).

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

The square root of 687684 is about 829.2671463407. The cubic root of 687684 is about 88.2665814274.

The spelling of 687684 in words is "six hundred eighty-seven thousand, six hundred eighty-four".