jackpot up to $42,000!! who wouldn't want that! but seriously guessing the 6 last symbols might take years before you could even guess it. you'd be luckiest person alive to guess it in less than a year. a combination of 10 numbers and 26 letters is a lot, thus the reason why alphanumberic is used for its harder to guess. good luck.
It's 10 digits and 6 numbers per symbol.
I think the probability of guessing would be 16
6, which is 1/16777216