Twenty-one of them, and twenty to thirty untransformed werewolves. It would be all depend on how skilled the werewolves were at duelling while in human form, and the Order would either have equal numbers, or be outnumbered. And if anyone got bitten...even if the "wolves were human, there would still be repercussions. Hermione felt a cold chill come over her and she hugged herself, eyes sweeping over the others and falling to rest on Draco. He still stared at Remus, but he looked hunched and crumpled again, gnawing nervously on his lip.