6687997865 has 8 divisors (see below), whose sum is σ = 8041367880. Its totient is φ = 5339884672.

The previous prime is 6687997847. The next prime is 6687997909. The reversal of 6687997865 is 5687997866.

It can be written as a sum of positive squares in 4 ways, for example, as 3932167849 + 2755830016 = 62707^2 + 52496^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6687997865 - 2⁶ = 6687997801 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1311404 + ... + 1316493.

It is an arithmetic number, because the mean of its divisors is an integer number (1005170985).

Almost surely, 2^6687997865 is an apocalyptic number.

It is an amenable number.

6687997865 is a deficient number, since it is larger than the sum of its proper divisors (1353370015).

6687997865 is a wasteful number, since it uses less digits than its factorization.

6687997865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2628411.

The product of its digits is 274337280, while the sum is 71.

The square root of 6687997865 is about 81780.1801477595. The cubic root of 6687997865 is about 1884.0772632256.

Subtracting from 6687997865 its reverse (5687997866), we obtain a palindrome (999999999).

The spelling of 6687997865 in words is "six billion, six hundred eighty-seven million, nine hundred ninety-seven thousand, eight hundred sixty-five".