687866 has 4 divisors (see below), whose sum is σ = 1031802. Its totient is φ = 343932.

The previous prime is 687847. The next prime is 687893. The reversal of 687866 is 668786.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 668786 = 2 ⋅334393.

It can be written as a sum of positive squares in only one way, i.e., 687241 + 625 = 829^2 + 25^2 .

It is a super-3 number, since 3×687866³ = 976411274312333688, which contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 171965 + ... + 171968.

2⁶⁸⁷⁸⁶⁶ is an apocalyptic number.

687866 is a deficient number, since it is larger than the sum of its proper divisors (343936).

687866 is a wasteful number, since it uses less digits than its factorization.

687866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343935.

The product of its digits is 96768, while the sum is 41.

The square root of 687866 is about 829.3768745269. The cubic root of 687866 is about 88.2743675137.

The spelling of 687866 in words is "six hundred eighty-seven thousand, eight hundred sixty-six".