How is winning the Mega Lotto only 1 in 176,000,000?

So there are 5 numbers (1-56) and 1 Mega number (1-46). So the chances of you getting the first 5 numbers are 56 * 55 * 54 * 53 * 52 = Just over 458 Million. You also have to get the Mega Number, so multiply that number by 46, and you get 21 billion. Wouldn't the winning chance be 1 in 21 billion instead?