I left a 20 mg ir adderall (dextroamphetamine and racemic amphetamine) outside, is it still safe to take?

Depends: Some people's 'outside' is cleaner and more protected than others. Inside is not necessarily less risky if out of bottle. It depends on what happened to it. It's probably ok but there's no way to be sure. In today's world it's hard to trust things in sealed containers even - so go with your feelings. If you feel ok with it, fine. If not, don't make yourself worry. Be well!