The two numbers you multiply together to equal 391 are 17 by 23.
17
17
83
Well, well, well, looks like we've got a little math puzzle on our hands. The two numbers you're looking for are 17 and 12. They may not be the life of the party, but they sure know how to add up and multiply like nobody's business.
-17
87
53
13
-1
87
-17
-17
13
47
47
-25