151

This number is a prime.

The highest snooker break in competition is 151 by Wally West in the final of a club handicap at the Hounslow Lucania Club in 1976. Although 147 is considered the maximum possible, he had a free ball in the second frame and potted the green as an extra red followed by the brown ball, 14 reds and blacks with a pink off the final red and the last six colours for a total clearance. [Homewood]