18 is one of the numbers that has 6 and 2 as its factors, but lacks 12 as one
A number with 12 as a factor has 6 and 2 as ones since 12 can be simplified to 6 times 2(60 for example has 12 times 5, while the 5 can't be simplified, 12 can and it simplifies to 6 times 2)
