687813 has 12 divisors (see below), whose sum is σ = 1067040. Its totient is φ = 392952.

The previous prime is 687809. The next prime is 687823. The reversal of 687813 is 318786.

It is not a de Polignac number, because 687813 - 2² = 687809 is a prime.

687813 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687823) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2193 + ... + 2486.

It is an arithmetic number, because the mean of its divisors is an integer number (88920).

2⁶⁸⁷⁸¹³ is an apocalyptic number.

It is an amenable number.

687813 is a deficient number, since it is larger than the sum of its proper divisors (379227).

687813 is a wasteful number, since it uses less digits than its factorization.

687813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4696 (or 4689 counting only the distinct ones).

The product of its digits is 8064, while the sum is 33.

The square root of 687813 is about 829.3449222127. The cubic root of 687813 is about 88.2721002787.

The spelling of 687813 in words is "six hundred eighty-seven thousand, eight hundred thirteen".