Well, at the current market rate of 17.0397 the full amount of bitcoin equals to :$357,833,700
If certain ideals are correct that they will be worth 1,000 then:21,000,000,000.
That seems like a good number.
If BTC became the new world reserve currency, try: 2,000,000,000,000,000
2,000,000,000,000,000/21,000,000 = 95,238,095 per BTC.