686191 has 12 divisors (see below), whose sum is σ = 775656. Its totient is φ = 606320.

The previous prime is 686177. The next prime is 686197. The reversal of 686191 is 191686.

It is a happy number.

It is not a de Polignac number, because 686191 - 2⁹ = 685679 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686197) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6360 + ... + 6466.

It is an arithmetic number, because the mean of its divisors is an integer number (64638).

2⁶⁸⁶¹⁹¹ is an apocalyptic number.

686191 is a deficient number, since it is larger than the sum of its proper divisors (89465).

686191 is a wasteful number, since it uses less digits than its factorization.

686191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182 (or 171 counting only the distinct ones).

The product of its digits is 2592, while the sum is 31.

The square root of 686191 is about 828.3664647968. The cubic root of 686191 is about 88.2026579345.

The spelling of 686191 in words is "six hundred eighty-six thousand, one hundred ninety-one".