What is the similarity between 85,17,19,4 and 2?

You can obtain the a number for which they all divisors by calculating the least common multiple.

This way:

85 = 5*17*1

17=17*1

19=19*1

4=2^2 * 1

2=2*1

The least common multiple is: 5*17*19*2^2 = 6,460.

Then 84, 17, 19, 4 and 2 are all divisors of 6,460.