Seven standard "riffle" shuffles are needed to effectively randomize a 52-card deck.

https://lemmy.dbzer0.com/post/34667105

Seven standard "riffle" shuffles are needed to effectively randomize a 52-card deck. - Divisions by zero

Lemmy

What if I just tossed the cards into the air and then picked them up? Would one toss be sufficient? 🤔
No. Surprisingly much of the order is preserved.