There isn't a last letter it goes on forever.
http://wiki.answers.com/Q/What_is_the_full_number_...

The symbol p is called pi and is approximately equal to 22/7 or 3.141592654. Thanks for asking
http://www.chacha.com/question/whatis314aspie

The value of π has been known in some form since antiquity. As early as the 19th century BC, Babylonian mathematicians were using π = 25⁄8, which is within 0.5% of the
http://answers.yahoo.com/question/index?qid=200703...
