686681217 has 12 divisors (see below), whose sum is σ = 1023869184. Its totient is φ = 443019960.

The previous prime is 686681213. The next prime is 686681231. The reversal of 686681217 is 712186686.

It is a happy number.

686681217 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 686681217 - 2² = 686681213 is a prime.

It is not an unprimeable number, because it can be changed into a prime (686681213) 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, 1230333 + ... + 1230890.

It is an arithmetic number, because the mean of its divisors is an integer number (85322432).

Almost surely, 2^686681217 is an apocalyptic number.

It is an amenable number.

686681217 is a deficient number, since it is larger than the sum of its proper divisors (337187967).

686681217 is a wasteful number, since it uses less digits than its factorization.

686681217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2461260 (or 2461257 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The square root of 686681217 is about 26204.6029735236. The cubic root of 686681217 is about 882.2365701972.

The spelling of 686681217 in words is "six hundred eighty-six million, six hundred eighty-one thousand, two hundred seventeen".