I looked that up earlier today. AFAIK, a dozen American men walked on the moon. Only four are still living. Another dozen orbited the moon. Six were command module pilots who went to the moon but stayed with the the ship while the other two crewmen descended to the moon in the Lunar module. Six others orbited the moon as dress rehearsals for the main event. I’m not sure Apollo 13 figures in there, as Jim Jowell made two trips to the moon: One on Apollo 8 and the other on the ill-fated 13.
I’m someone else will chime in to sort it all out.
Apollo 8 and 10 also orbited the moon without landing. There were 3 on board each. Apollo 13 flew by the moon with 3 on board, but one (Jim Lovell) had already been there on Apollo 8. So that’s 14 by my count, who only orbited or flew by the moon in addition to the 12 who walked its surface.