Atheists, and I am one, tend to be rationalists.
Rationalists would tend not to play the lottery, although I play the lottery.
Atheists, in spite of what George H.W. Bush might wish to represent, are actually human beings, (and actually have ethics) and in spite of their best intentions, still do irrational things, like play the lottery.
I play the lottery mostly because the improbability of winning the lottery is not quite as improbable as things which already exist. But I'm actually not necessarily proud of playing the lottery, since it is irrational.
The tendency towards rationalism would tend to suggest that atheists are under represented among lottery players and therefore are under represented among lottery winners, compared to the population. This doesn't mean that there are no atheists who play the lottery, just fewer atheists who play than religious people who play.
Of course winners who are religious, tend to announce their religions. Many religious people attribute their good luck - and all of their opinions about everything else - to God. (Our country is fighting a criminal war to steal oil because the President of the United States has declared that God wants him to fight the war.) Jack Whitaker for instance made a big deal about his church - tithing 10% - and the rest is history.
If I won the lottery I have no intention of announcing my religious preferences or anything else about myself. I'll keep my mouth shut and do my best with the money. Thus if I won, you would have no further information on the atheism of winners.