687656773 has 4 divisors (see below), whose sum is σ = 688331308. Its totient is φ = 686982240.

The previous prime is 687656771. The next prime is 687656777. The reversal of 687656773 is 377656786.

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 536292964 + 151363809 = 23158^2 + 12303^2 .

It is a cyclic number.

It is not a de Polignac number, because 687656773 - 2¹ = 687656771 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687656771) by changing a digit.

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, 335736 + ... + 337777.

It is an arithmetic number, because the mean of its divisors is an integer number (172082827).

Almost surely, 2^687656773 is an apocalyptic number.

It is an amenable number.

687656773 is a deficient number, since it is larger than the sum of its proper divisors (674535).

687656773 is a wasteful number, since it uses less digits than its factorization.

687656773 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 674534.

The product of its digits is 8890560, while the sum is 55.

The square root of 687656773 is about 26223.2105776543. The cubic root of 687656773 is about 882.6541651934.

The spelling of 687656773 in words is "six hundred eighty-seven million, six hundred fifty-six thousand, seven hundred seventy-three".