687686 has 8 divisors (see below), whose sum is σ = 1085880. Its totient is φ = 325728.

The previous prime is 687683. The next prime is 687691. The reversal of 687686 is 686786.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 687686.

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

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9011 + ... + 9086.

It is an arithmetic number, because the mean of its divisors is an integer number (135735).

2⁶⁸⁷⁶⁸⁶ is an apocalyptic number.

687686 is a deficient number, since it is larger than the sum of its proper divisors (398194).

687686 is a wasteful number, since it uses less digits than its factorization.

687686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18118.

The product of its digits is 96768, while the sum is 41.

The square root of 687686 is about 829.2683522238. The cubic root of 687686 is about 88.2666669963.

Subtracting from 687686 its reverse (686786), we obtain a square (900 = 30²).

The spelling of 687686 in words is "six hundred eighty-seven thousand, six hundred eighty-six".