Recently the Bounties of all the Yonko as well as Whitebeard and Roger were revealed.
Blackbeard has the lowest Bounty among the Yonko.
Shanks’ Bounty is 4,048,900,000 Berries.
Big Mom’s Bounty is 4,388,000,000 Berries.
Kaido’s Bounty is 4,611,100,000 Berries.
Whitebeard’s Bounty was 5,046,000,000 Berries.
Gol D. Roger’s Bounty was 5,564,800,000 Berries. Roger is the current holder of the highest bounty in the series, stated to be unsurpassed by any pirate.
Since Luffy has been hyped up to be even more powerful than Roger at the end of the series, and since we know Oda likes to play with the numbers 5 and 6 because they can represent “Gomu” in Japanese (5 = Go, 6 = Mu), maybe Oda will make Luffy’s final Bounty as 5,600,000,000 Berries.
I think this is plausible considering Oda’s playfulness with Luffy always being around the numbers 5 and 6.
Examples of Oda playing with Luffy and #56:
Luffy’s number in the colliseum at Dressrosa: 0556
Number of people in the Straw Hat Grand Fleet: initially 5600 (now 5640, might end up at 5656)
Katakuri’s Bounty: 1,057,000,000 (hinting with the “57” that he’s slightly better/more powerful than Luffy).
Barto Club (Bartolomeo’s fanboy crew) having exactly 56 members
*Theory by Dynastian98