1, 3, 9, 27
1,2,3,5,6,10,15,30
1,2,3,4,6,12
I'm pretty sure the answer would be 1,2,4,16 (:
We can't answer this accurately if you don't tell us the groups to choose from.
13 and 19 aren't composite. 1,2,5,10 1,13 1,2,3,6,9,18 1,19
the set of factors
As a product of its prime factors: 2*3*3*5*139 = 12510 or as 2*32*5*139 = 12510
1,3,9,27
One and the number itself.
Any prime number only has two factors, one and the number itself.
1 and 71
1,2,3,4,6,9,12,18,36