686786 has 4 divisors (see below), whose sum is σ = 1030182. Its totient is φ = 343392.

The previous prime is 686773. The next prime is 686789. The reversal of 686786 is 687686.

686786 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 511225 + 175561 = 715^2 + 419^2 .

It is not an unprimeable number, because it can be changed into a prime (686789) by changing a digit.

686786 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, 171695 + ... + 171698.

2⁶⁸⁶⁷⁸⁶ is an apocalyptic number.

686786 is a deficient number, since it is larger than the sum of its proper divisors (343396).

686786 is a wasteful number, since it uses less digits than its factorization.

686786 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343395.

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

The square root of 686786 is about 828.7255275421. The cubic root of 686786 is about 88.2281442398.

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

The spelling of 686786 in words is "six hundred eighty-six thousand, seven hundred eighty-six".