If the total money in circulation is about $75 trillions

https://www.quora.com/What-is-the-total-amount-of-money-in-the-world?srid=Vkiw

and assuming that Bitcoin gets 50% of this, it would mean that we have Bitcoin's market cap at $37.5 trillions. By using some proportions, it means that 1 BTC would be equal to $2,343,750.