I don't believe they've ever named it; it is indeed "supermassive" (around 2.3 billion of our suns). The supermassive black hole at the center of the Milky Way

I don't believe they've ever named it; it is indeed "supermassive" (around 2.3 billion of our suns). The supermassive black hole at the center of the Milky Way is called Sagittarius A* ("Sagittarius A-Star"), the only named supermassive black hole I could find in any reports.