You can use complimentary counting, first let S = total number of possible subsets.

Let N = the number of subsets with no prime number, then the answer we are looking for is S - N.

S = 2^18 since there are 18 items.

N is any set with 4, 6, 8, 9, 10, 12, 14, 15, 16, 18.

There are a total of 10 items.

So S - N = 2^18 - 2^10

**261120 subsets**