The first one is 7.
The 57th one is 399.
There are 57 of them.
Ten of them.
There are five of them, including the number 1.
1and 11564
1, 4, 9, 16, 25, 36
There are exactly 5,761,455 prime numbers below 100,000,000, the first being two, and the last 99,999,989.