I count 55, starting in 1789. They occur every four years.
five
George Washington is the president that appointed the most Supreme Court Justices. There have been only seven US Presidents that served only one term.
4 years
not one
As of my knowledge cutoff date in 2021, there have been no vice presidents of the United States who were Rhodes scholars.
As a group one-term presidents are not so successful which is why they were one-term presidents. Polk refused to run for a second term and he was probably the most successful one-termer. Taft would very probably have won a second term if Theodore Roosevelt had supported him instead of breaking with with his party and running as an independent against him.
I am not quite sure what " went for" means to you. Only two presidents announced early in their administration that they would not seek a second term and they were James Polk and Rutherford Hayes.
Including the one in office in 1920 and up to and including Barack Obama, there have been 17 U.S. Presidents.
No, that is not a requirement.
6
There has only been one president of Uzbekistan so far.
Eritrea has only had one president so far.
one JFK