687771 has 20 divisors (see below), whose sum is σ = 1175152. Its totient is φ = 392688.

The previous prime is 687767. The next prime is 687773. The reversal of 687771 is 177786.

It is not a de Polignac number, because 687771 - 2² = 687767 is a prime.

It is a Duffinian number.

687771 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (687773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 40 + ... + 1173.

2⁶⁸⁷⁷⁷¹ is an apocalyptic number.

687771 is a deficient number, since it is larger than the sum of its proper divisors (487381).

687771 is a wasteful number, since it uses less digits than its factorization.

687771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1232 (or 1223 counting only the distinct ones).

The product of its digits is 16464, while the sum is 36.

The square root of 687771 is about 829.3196006366. The cubic root of 687771 is about 88.2703035191.

The spelling of 687771 in words is "six hundred eighty-seven thousand, seven hundred seventy-one".