PS.... I wrote:
"Martin-888" wrote:
I think joeu is right, it is 2240 tickets that I would need
to make sure that I win 4 out of 6

Actually, the correct number is 5456.
[....]
there are 6090 ways to match 4 of 6 drawn numbers, and there are 1,947,792
total combinations of 6 of 36 numbers, what the
player chooses. So the probability is 6090/1947792.

I suspect those two statements might cause some confusion. Let me
clarify....

There are 6090 combinations that match 4 of a __specific__ 6 drawn numbers.

But we need 5456 combinations (carefully chosen) to match at least 4 of
__all_possible__ 6 drawn numbers.