686681191 has 16 divisors (see below), whose sum is σ = 805489920. Its totient is φ = 573249600.

The previous prime is 686681189. The next prime is 686681213. The reversal of 686681191 is 191186686.

It is a happy number.

It is not a de Polignac number, because 686681191 - 2¹ = 686681189 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 (686681591) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33516 + ... + 49966.

It is an arithmetic number, because the mean of its divisors is an integer number (50343120).

Almost surely, 2^686681191 is an apocalyptic number.

686681191 is a deficient number, since it is larger than the sum of its proper divisors (118808729).

686681191 is a wasteful number, since it uses less digits than its factorization.

686681191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16614.

The product of its digits is 124416, while the sum is 46.

The square root of 686681191 is about 26204.6024774275. The cubic root of 686681191 is about 882.2365590624.

The spelling of 686681191 in words is "six hundred eighty-six million, six hundred eighty-one thousand, one hundred ninety-one".