686805813 has 12 divisors (see below), whose sum is σ = 993679180. Its totient is φ = 457119936.

The previous prime is 686805809. The next prime is 686805817. The reversal of 686805813 is 318508686.

686805813 is a `hidden beast` number, since 6 + 8 + 68 + 0 + 581 + 3 = 666.

It is an interprime number because it is at equal distance from previous prime (686805809) and next prime (686805817).

It can be written as a sum of positive squares in 2 ways, for example, as 22867524 + 663938289 = 4782^2 + 25767^2 .

It is not a de Polignac number, because 686805813 - 2² = 686805809 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 (686805817) 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, 56728 + ... + 67761.

Almost surely, 2^686805813 is an apocalyptic number.

It is an amenable number.

686805813 is a deficient number, since it is larger than the sum of its proper divisors (306873367).

686805813 is a wasteful number, since it uses less digits than its factorization.

686805813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 125108 (or 125105 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 45.

The square root of 686805813 is about 26206.9802342811. The cubic root of 686805813 is about 882.2899265908.

The spelling of 686805813 in words is "six hundred eighty-six million, eight hundred five thousand, eight hundred thirteen".