POTUS Quiz

Monday is Presidents Day here in the United States.
Here are several questions about the Presidents of the United States.
How many of them can you answer?

Post your answers in a comment, numbering them by the questions.
If a follow-up question is in parentheses, put that answer in parentheses.
I will post answers to this later.

1. What is the most common presidential first name? (How many times?)

2. Which President was preceded and succeeded by the same person?

3. Two presidents with similar last names, from the same state, were the only two with this first name:

4. Who is the only man to be two presidents?

5. Which President served the shortest time in office?

6. Which President served the longest time in office?

7. Which presidents were father & son? Name the pair(s)

8. Which presidents were grandfather & grandson? Name the pair(s)

9. Which presidents had the same last name, but were not related?

10. Which U.S. presidents had been presidents of Ivy League universities? (Which schools?)

11. Which presidents' elections were decided by Congress, because no one had a majority of electoral votes?

12. Who was the only U.S. President to resign?

13. Which President had not been elected as either President of Vice President?

14. Which presidents had the shortest last names?

15. Which presidents had the longest last names?

16. Which President was a bachelor?

17. Who was the first President to live in the White House?

18. Which President has a state named after him?

19. Which president has a foreign capital named after him? (Which capital?)

20. Which President was sworn in by his father?