3a312c46_tal_Commodities___Bitcoin_Wiki__Ideal_Implementation
[Property] Divisible B. [Notes] 2,100,000,000,000,000 individual units (2.1 Quadrillion); if necessary this could be increased with the agreement of miners and clients. [Ideal Implementation] 
should be as close to infinitely divisible as possible
Ideal Properties of Digital Commodities - Bitcoin Wiki
Ideal Implementation