How many combinations can you make out of 26 letters?

There are 26! (which means 26*25*24 all the way to 1) permutations.

this comes to 403,291,461,100,000,000,000,000,000 different combinations. If it takes you thirty seconds to write out one combination, then it would take 383,123,823,100,000,000,000 YEARS to write all the combinations. To put this into context, the universe (and possibly time itself) is only 13,700,000,000 years old.