You are requested to partition the set of 10 digits (0,1,…,9) into a maximal number of subsets, such that in each set it is possible to create a prime number
using all its members.
What is the highest prime thus created?
Well, Jer and Tomarken interpreted this to mean that the prime had to be formed through digital concatenation. And, yes, I expect that is what the puzzle author probably meant to say.
But 6 is not maximal if other operations are allowed. For instance, here are 7 sets: