Echinopsis hybrid. Treat as any other cactus. Best in full to mostly full sun, well draining soil (LOTS of pumice ideally) and water weekly in summers, and much less in winters (unless you live in Palm Springs, then water weekly in winters, too). Most yellow is scaring from age, but you could be getting some rot/damage if over watering.. .feel it (careful for spines) for softness.. .if soft- bad.

Thank you!! I will treat it like so.