684688 has 10 divisors (see below), whose sum is σ = 1326614. Its totient is φ = 342336.

The previous prime is 684683. The next prime is 684713. The reversal of 684688 is 886486.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 589824 + 94864 = 768^2 + 308^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 684688.

It is not an unprimeable number, because it can be changed into a prime (684683) by changing a digit.

684688 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21381 + ... + 21412.

2⁶⁸⁴⁶⁸⁸ is an apocalyptic number.

It is an amenable number.

684688 is a deficient number, since it is larger than the sum of its proper divisors (641926).

684688 is a wasteful number, since it uses less digits than its factorization.

684688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42801 (or 42795 counting only the distinct ones).

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

The square root of 684688 is about 827.4587603017. The cubic root of 684688 is about 88.1382125621.

The spelling of 684688 in words is "six hundred eighty-four thousand, six hundred eighty-eight".