In how many ways can four aces be drawn from a deck of cards? (order is not important.)

Let's imagine that we have in the deck 52 cards. So what we need to do is to make a kind of "progression".So let me explain this by doing the procedure. we can use is like this: 
4/52 * 3/51 * 2/50 * 1/49 = 
24 / 6497400 = 
1 / 270725 
3.694e-6