A Mastermind Game Ripoff

Sometimes I play this Clubhouse 51 Games game on my Nintendo Switch. It’s actually a decent set of board games, card games, etc. I especially like the Othello ripoff and the Mastermind ripoff. They have other names. Sometimes I win Mastermind. Today, I won with three guesses left!

With six colors of pegs and four spaces to fill (with no color repeats), how many possible combinations are there?