22 years. wow. i had no idea cats live that long. but i think it is a different thing for house cats vs outdoor cats. Think our oldest cat was around 10 years old, but he looked like he gone through wars. Also it is a weird thing, we had 3 cats that got to "old" age and all of them just left and never come back.
It's quite unusual for a cat to live so long. I think the longest recorded is 30 but the average is something like 12-15 I think. Cats have a tendency to do that, slink away and die somewhere; I'm not sure why. Merlin is an indoor cat and only goes outside if we are with him, usually daily, but not these days. We would be devastated if he just disappeared.