16 and -5
71
When the "factors" of a number are listed, the list is usually restricted to positive factors. Then there would be no answer to the question, because no group of positive numbers can add up to make zero.
1 x 143 11 x 13
99 factors to [3 3 11] 121 factors to [11 11] Common factors [11] Answer is 11. ■
-911
21
11 x 13
13 and -2
121 = 11 x 11
1 x 121, 11 x 11 = 121
16 and -5
71
1 and 121 is one possible pair. 11 and 11 is the other.
33 and 1 -33 and -1 11 and 3 -11 and -3
11 times 19 = 209
44 is equal to 11 x 2 x 2. The product of any set of prime factors of a number is equal to the number itself.