Translation of "Mega" in English

Eles são os líderes das mega-igrejas com dezenas de milhares de membros.

They're the leaders of megachurches with tens of thousands of members.

O rapaz tem uma sorte danada: acertou todos os números na mega-sena e levou o prêmio sozinho.

The kid has amazing luck. He guessed all the lottery numbers right and took the prize by himself.