[noggin]

This would only be true if bitcoin were infinitely divisible.

In actuality the block reward will eventually be one 'satoshi' (one hundred-millionth of a bitcoin); then, when it's next due to be halved, dividing by 2 with a fixed precision of 8 decimal places will take the reward down to a value of zero.

[chrismorgan]

See https://en.bitcoin.it/wiki/Controlled_supply#Projected_Bitco... for a table of rewards.

Note that it is possible, by consensus, for the satoshi to become divisible, though I can’t see it becoming infinitely divisible. (From that page: “The total number of bitcoins, as mentioned earlier, has an asymptote at 21 million, due to a technical limitation in the data structure of the blockchain - specifically the integer storage type of the transaction output, this exact value would have been 20,999,999.9769 bitcoin. Should this technical limitation be adjusted by changing the width of the field, the total number will still only approach or be a maximum of 21 million.”)