How many earthquakes has there been?
You don't specify in your question where exactly you want to know how many Earthquakes there have been. No one can be sure exactly how many Earthquakes there have been on Earth, because some of them must have been before recorded History.
It is impossible to determine how many earthquakes there have been throughout history. Earthquakes occur frequently all over the earth, including deep under the ground. Many of these may not be felt by people and barely register on scientific equipment, but they are still earthquakes. There are generally a few dozen earthquakes EACH DAY. See the link for the last 7 days earthquakes. 12