[pnispel]

Something I've been thinking about is if the entirety of currency in the US was represented in bitcoin (bitcoins were the currency rather than dollars), how much would each be worth?

So there is about $1.2 trillion in circulation [1] and the cap for bitcoins is 21,000,000

1.2 trillion / 21 million ~= $57,142 per bitcoin

Is this right, or am I missing something?

[1] - http://www.federalreserve.gov/faqs/currency_12773.htm

[conception]

1.2 trillion in physical currency. You want the M2 number (http://www.tradingeconomics.com/united-states/money-supply-m...) which is about 11 trillion.

So about another order of magnitude there.