Goroawase doesn't help with the important part of the bounty.
Oda uses it for the middle numbers.
So, not super interesting.
But anyways...
Rayleigh:
-"Dark King"
冥王 => めいおう => 5 0
-"Silvers"
シル バーズ => 4 6 8 2
Teach:
-"Blackbeard"
黒ひげ => くろひげ => 9 6 1 5
Mihawk:
-"Hawk eyes"
鷹の目 => たか の め => 3 5 2 6
-"Dracule"
ジュラキュール => 1 0 6 9 6
So...
Rayleigh: 3,500,000,000 or 3,468,200,000 ?
Blackbeard: 4,961,500,000 ?
Mihawk: 2,352,000,000 or 2,106,960,000 ?
You can switch the 3 billions into 2 billions, 2 billions into 3 billions, and so on.
You can add leading 0's to some parts.
Doesn't really matter.