What’s Ultraman’s real name?

I’m curious about it especially since every other ultra has a name despite the fact most of them are just referred to as Ultraman or Ultrawomen throughout their series instead of their actual name which is for the title (Keep in mind this is from what I remember and I haven’t watched anything Ultraman related in a while so I’m probably wrong) and if they’re original Ultraman doesn’t have an official name then what name would you give him?