686683517 has 4 divisors (see below), whose sum is σ = 739505340. Its totient is φ = 633861696.

The previous prime is 686683513. The next prime is 686683531. The reversal of 686683517 is 715386686.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 331021636 + 355661881 = 18194^2 + 18859^2 .

It is not a de Polignac number, because 686683517 - 2² = 686683513 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 (686683513) 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, 26410892 + ... + 26410917.

It is an arithmetic number, because the mean of its divisors is an integer number (184876335).

Almost surely, 2^686683517 is an apocalyptic number.

It is an amenable number.

686683517 is a deficient number, since it is larger than the sum of its proper divisors (52821823).

686683517 is a wasteful number, since it uses less digits than its factorization.

686683517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52821822.

The product of its digits is 1451520, while the sum is 50.

The square root of 686683517 is about 26204.6468589065. The cubic root of 686683517 is about 882.2375551966.

The spelling of 686683517 in words is "six hundred eighty-six million, six hundred eighty-three thousand, five hundred seventeen".