687311965 has 4 divisors (see below), whose sum is σ = 824774364. Its totient is φ = 549849568.

The previous prime is 687311953. The next prime is 687311981. The reversal of 687311965 is 569113786.

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 426876921 + 260435044 = 20661^2 + 16138^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-687311965 is a prime.

It is a super-2 number, since 2×687311965² = 944795474464322450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68731192 + ... + 68731201.

It is an arithmetic number, because the mean of its divisors is an integer number (206193591).

Almost surely, 2^687311965 is an apocalyptic number.

It is an amenable number.

687311965 is a deficient number, since it is larger than the sum of its proper divisors (137462399).

687311965 is a wasteful number, since it uses less digits than its factorization.

687311965 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137462398.

The product of its digits is 272160, while the sum is 46.

The square root of 687311965 is about 26216.6352722847. The cubic root of 687311965 is about 882.5066123674.

The spelling of 687311965 in words is "six hundred eighty-seven million, three hundred eleven thousand, nine hundred sixty-five".