Arguably Joker is the number, and like Ace is 1 you might use 0 or 14 depending on math preferences as a surrogate number (or stick to the character designations like A, K, Q, J).
Decks with four jokers typically have suited jokers. Decks with two are typically (though not always) red/black and could be given arbitrary suits (say hearts/spades).
Decks with four jokers are often suited (just as the most common decks with two jokers are red/black), so a deck with three jokers you could treat as suited jokers that are missing a suit.
