# Number of combinations of 30 dice rolls

You roll thirty dice.
How many different possible combinations can be rolled?
Order does not matter

I think it's 6^30 choose 30, so:
$$\frac{(6^{30})!}{(6^{30}-30)!(30!)}$$

Also, perhaps the more important part of my question - any idea how to approximate this? The numbers involved are very large