How many Bitcoin are there?
21,000,000 Bitcoins will ever exist.
How many Bitcoin will there ever be?
A total of 21,000,000 so between 2019 and 2140 another 3 millions are mined and that's IT.
How many are considered "missing"?
According to a recent study by Chainalysis, a blockchain analysis company that specializes in building trust in blockchains, reported that around 4 million bitcoins are lost and are irretrievable. Sep 14, 2019.
It's interesting, there are coins that are "missing". Meaning, the wallet they are in hasn't been touched by anyone in a certain period of time. The longer they go untouched, the more likely it seems they are lost. Meaning the keys are missing, either lost or forgotten. In the 2017 run up to almost 20K per BTC, there were MANY stories from sad people who lost thousands to millions of Bitcoin. Suddenly, old computers and laptops where being dug up from various places like the city dump.