There seems to be some misunderstanding of what the problem is asking.
So, we have 3 x 6 x 9 x 12 x 15 x 18 = 524,880
If we break that all down...
3 x 3 x 2 x 3 x 3 x 3 x 2 x 2 x 3 x 5 x 3 x 2 x 3
Put that all in order...
24 x 38 x 5
4 twice
16
4 x 9 = 36 twice
4 x 81 = 324 twice
4 x 6561 = 26,244
16 x 9 = 144
16 x 81 = 1296
16 x 6561 = 104,976
I'm out of time to find the rest, but I bet you can!
Louis M.
The answer is 14. I couldn't work out the correct answer too..08/03/19