How many hashes create one Bitcoin?
These charts show the approximate network hash rate on the left axis: http://bitcoin.sipa.be/
We know the network adjusts for 25 new bitcoins per 10 minutes.
Together this provides enough info to give an approximate answer to your question:
hashes per bitcoin = (network hash rate) / (25 BTC per 10 minutes) = (180 * Th / s) / (25 * BTC / (600 * s) ) = 180 * 600 / 25 * Th / s / BTC * s = 2,700 Th / BTC = 2,700,000,000,000,000 h/BTC
That is read from the charts I linked to. It is the current network hash rate in terra-hash-per-second, as the charts show this number continually changes as miners come and go.
Thanks! I think I have to dig deeper into the function of BC to understand everything!
A good and simple website to calculate how much bitcoin can be created with what machine can be found at: http://www.alcula.com/calculators/finance/bitcoin-mining/
Difficulty changes regularly, but there are calculators that take all current factors into account:
As of today (17 Jan 2017): a theoretical 1,581 TH/s (equivalent of running a hundred Antminer S9's) will return 1 BTC in a day.
Tomorrow, it will be different.