686309879 has 4 divisors (see below), whose sum is σ = 699259176. Its totient is φ = 673360584.

The previous prime is 686309863. The next prime is 686309891. The reversal of 686309879 is 978903686.

686309879 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 is a cyclic number.

It is not a de Polignac number, because 686309879 - 2⁴ = 686309863 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 (686309179) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6474569 + ... + 6474674.

It is an arithmetic number, because the mean of its divisors is an integer number (174814794).

Almost surely, 2^686309879 is an apocalyptic number.

686309879 is a deficient number, since it is larger than the sum of its proper divisors (12949297).

686309879 is a wasteful number, since it uses less digits than its factorization.

686309879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12949296.

The product of its (nonzero) digits is 3919104, while the sum is 56.

The square root of 686309879 is about 26197.5166571185. The cubic root of 686309879 is about 882.0775119001.

The spelling of 686309879 in words is "six hundred eighty-six million, three hundred nine thousand, eight hundred seventy-nine".