You have already been correctly told that the number of fractional parts of a bitcoin satoshi enough to theoretically have enough for all the inhabitants of our planet, at least in a small amount. But in fact, there are no insurmountable technical problems in dividing satoshi into even smaller fractions, and thus everyone may well have enough bitcoin. There are more problems with how useful it will be to use such small amounts, given the transaction fees that are necessary to pay the work of the miners.