Jesus could have saved the world alone. The moment He stepped out of the water of the Jordan, He could have walked off, and just started His ministry.
It wasn't a lack of ability, power, or mental resources. He was given everything He needed by the Father:
Jesus gave them this answer: “Very truly I tell you, the Son can do nothing by himself; he can do only what he sees his Father doing, because whatever the Father does the Son also does. For the Father loves the Son and shows him all he does. Yes, and he will show him even greater works than these, so that you will be amazed. (John 5:19-20)