687856313 has 16 divisors (see below), whose sum is σ = 717985296. Its totient is φ = 658544640.

The previous prime is 687856277. The next prime is 687856319. The reversal of 687856313 is 313658786.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 91910569 + 595945744 = 9587^2 + 24412^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-687856313 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (687856319) 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, 442145 + ... + 443697.

It is an arithmetic number, because the mean of its divisors is an integer number (44874081).

Almost surely, 2^687856313 is an apocalyptic number.

It is an amenable number.

687856313 is a deficient number, since it is larger than the sum of its proper divisors (30128983).

687856313 is a wasteful number, since it uses less digits than its factorization.

687856313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1804.

The product of its digits is 725760, while the sum is 47.

The square root of 687856313 is about 26227.0149464250. The cubic root of 687856313 is about 882.7395313170.

The spelling of 687856313 in words is "six hundred eighty-seven million, eight hundred fifty-six thousand, three hundred thirteen".