D&D: How Many Character Builds Are Possible?

According to Comicbook.com, "A Redditor with a talent for math figured out just how adaptive and diverse Dungeons & Dragons' character creation system is. Yesterday, the Reddit user u/Synergenesis made a post about the total number of possible Level 20 character builds you could make using the classes, subclasses, races, backgrounds, and other player options available to players in Dungeons & Dragons' current Player Handbook." This the ultimate knowledge for all Dungeons & Dragon nerds.