How many presidents have been impeach?

Answer 1

Andrew Johnson was impeached in 1868 for violating the Tenure of Office Act.

Bill Clinton was impeached in 1998 for perjury and obstruction of justice.

Note that Impeachment does not mean removal from office, it means that he is being investigated on suspicion of wrongdoing that may result in him being removed from office. In both of the above cases the President remained in office.

Richard Nixon was not impeached, he resigned before the impeachment proceedings being considered agaisnt him could begin.

Answer 2

Bill Clinton is the only president in history to be impeached. He's also the only president to ever cheat on the first lady while in office.