Surely it is. Each BTC has 100.000.000 of satoshis. 21.000.000 x 100.000.000 = 2.100.000.000.000.000 of satoshis, enough for all the world use it well. 1 Satoshi can values more than 1 currently cent. Probably the difficult would be to buy cheap things with BTCs, as 1 satoshi could value more than the price of cheap things like one fuit, one candy...