Answer:
19
Step-by-step explanation:
the only way u can get 19 is if you multiply 19x1 but other than that you cant get the number
the other numbers have more than one multiple but 19 only has one multiple
the only factors multiplyed that can make 19 is 1 and 19
15:1, 3, 5, 15
18:1, 2, 3, 6, 9, 18
22:1, 2, 11, 22
19:1, 19
take care
