Highest XP

It's been long since Pokémon GO has been released. Many players have reached level 40 by now. Unfortunately, I started the game a bit late and I'm stuck in 32. However, I want to know the maximum amount of XP collected by a player. I've heard that some players have earned 40 Million XP which is enough to complete the game twice. I know that there's no way to know the exact amount. But I want to know the highest amount you've seen. I believe an estimate can be done.

(I've only seen a maximum of 25.7M XP which is Level 40+5.7M earned)