687556 has 6 divisors (see below), whose sum is σ = 1203230. Its totient is φ = 343776.

The previous prime is 687551. The next prime is 687559. The reversal of 687556 is 655786.

It can be written as a sum of positive squares in only one way, i.e., 614656 + 72900 = 784^2 + 270^2 .

It is not an unprimeable number, because it can be changed into a prime (687551) by changing a digit.

687556 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 85941 + ... + 85948.

2⁶⁸⁷⁵⁵⁶ is an apocalyptic number.

It is an amenable number.

687556 is a deficient number, since it is larger than the sum of its proper divisors (515674).

687556 is a wasteful number, since it uses less digits than its factorization.

687556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171893 (or 171891 counting only the distinct ones).

The product of its digits is 50400, while the sum is 37.

The square root of 687556 is about 829.1899661718. The cubic root of 687556 is about 88.2611046757.

The spelling of 687556 in words is "six hundred eighty-seven thousand, five hundred fifty-six".