687845 has 8 divisors (see below), whose sum is σ = 843264. Its totient is φ = 538384.

The previous prime is 687839. The next prime is 687847. The reversal of 687845 is 548786.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 687845 - 2⁴ = 687829 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 687799 and 687808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687847) 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 7 ways as a sum of consecutive naturals, for example, 1229 + ... + 1698.

It is an arithmetic number, because the mean of its divisors is an integer number (105408).

2⁶⁸⁷⁸⁴⁵ is an apocalyptic number.

It is an amenable number.

687845 is a deficient number, since it is larger than the sum of its proper divisors (155419).

687845 is a wasteful number, since it uses less digits than its factorization.

687845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2979.

The product of its digits is 53760, while the sum is 38.

The square root of 687845 is about 829.3642143232. The cubic root of 687845 is about 88.2734691892.

The spelling of 687845 in words is "six hundred eighty-seven thousand, eight hundred forty-five".