沒有最大的質數! 質數是無限大的.
所知最大的是 2^32,582,657-1 (9,808,358 digits), Dr. Curtis Cooper and Dr. Steven Boone found it on September 6, 2006. It is called a Mercene prime, which is always of the form 2^n-1.
In fact, your computer can help find the next largest by joining Gimps. Dr. Cooper and Boone won $100,000 a second time! You can too!
For details, see:
http://www.mersenne.org/