 Find the LAST Prime NumberJuly 3 2014 at 12:42 PM  Al Gore Rhythm (no login)  

It is easy to see that there are an infinite number of prime numbers, so there is no last prime with respect to the usual ordering 2,3,5,7, &c.
BUT..... We can order the prime numbers in alphabetical order according to their name in English (ignoring spaces and hyphens).
So "three" comes before "twentythree" which comes before "two".
What is the *last* prime number in alphabetical order?
The names of the powers of ten are:
hundred, thousand, million, billion (10**9), trillion, quadrillion, quintillion, ..., decillion, undecellion, dodecillion, tredecillion, quattordecillion, ... vigintillion (10**63)
So the last prime should be close to two 2 x 10**63. (So you will need arbitrary precision math unless you want to use a list of prime numbers from the Internet).
You can use a probalistic primality test like Fermat's test.  
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