687789 has 6 divisors (see below), whose sum is σ = 993486. Its totient is φ = 458520.

The previous prime is 687787. The next prime is 687809. The reversal of 687789 is 987786.

It can be written as a sum of positive squares in only one way, i.e., 412164 + 275625 = 642^2 + 525^2 .

It is not a de Polignac number, because 687789 - 2¹ = 687787 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687787) 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 5 ways as a sum of consecutive naturals, for example, 38202 + ... + 38219.

It is an arithmetic number, because the mean of its divisors is an integer number (165581).

2⁶⁸⁷⁷⁸⁹ is an apocalyptic number.

It is an amenable number.

687789 is a deficient number, since it is larger than the sum of its proper divisors (305697).

687789 is a wasteful number, since it uses less digits than its factorization.

687789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76427 (or 76424 counting only the distinct ones).

The product of its digits is 169344, while the sum is 45.

The square root of 687789 is about 829.3304528353. The cubic root of 687789 is about 88.2710735679.

The spelling of 687789 in words is "six hundred eighty-seven thousand, seven hundred eighty-nine".