20999999.9769 BTC as the Genesis block is texhnically unspendable 😬 😉
Discussion
Those 2.31 million missing sats are due to the rounding down of the block subsidy to an integer number of sats. It doesn’t have anything to do with the unspendable 50 coins from the Genesis block.
Check out Pieter Wuille’s answer here for more unspendable/lost/unmined coins: https://bitcoin.stackexchange.com/questions/38994/will-there-be-21-million-bitcoins-eventually