686686 has 40 divisors (see below), whose sum is σ = 1411704. Its totient is φ = 246960.

The previous prime is 686671. The next prime is 686687.

686686 is nontrivially palindromic in base 10.

Its product of digits (82944) is a multiple of the sum of its prime factors (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686687) by changing a digit.

686686 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 in 19 ways as a sum of consecutive naturals, for example, 52816 + ... + 52828.

2⁶⁸⁶⁶⁸⁶ is an apocalyptic number.

686686 is an abundant number, since it is smaller than the sum of its proper divisors (725018).

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

686686 is a wasteful number, since it uses less digits than its factorization.

686686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54 (or 33 counting only the distinct ones).

The product of its digits is 82944, while the sum is 40.

The square root of 686686 is about 828.6651917391. The cubic root of 686686 is about 88.2238618565.

The spelling of 686686 in words is "six hundred eighty-six thousand, six hundred eighty-six".