When the stars line up, and the entrails are favorable, a single .22LR will stop about anything, DRT.
HOWEVER, when this doesn't happen, and that is often, the .22LR doesn't do a lot of the kind of damage that stops people. Kills them, yes, often. STOPS them, not so much.
The thing with the .22 is that for all the successes we hear about, there are volumes of failures we don't hear about. All the stories about how poachers kill deer with .22LR are based on facts, but one of the facts left out of the stories is how often a deer is shot, and lost.
If all you have is a .22 pistol, you aren't defenseless, not even remotely, but you ARE in a position of having a deadly weapon that is not a reliable fight stopper.
CCI Mini Mags are good quality ammo, and I would use them over any "bulk pack" stuff.
One fellow I knew, a retired State Trooper, chose a Ruger .22LR pistol (mark I) as his home defense gun. As it happened, he was an expert shot with it, and could "burst fire" and cut the eyes out of a silhouette target in about one second. His reasoning was that if nerve/brain damage from the bullets didn't stop someone, blinding them ought to at least slow them down...
Can't say I would recommend that, but it did seem to make sense to an impressionable youngster at the time..