99999
There are 3,265,920 numbers that can be formed using all the digits. The answer to the question will depend on which one of these.
There are 60480 numbers.
There are 4^6 = 4096 such numbers.
8.
If the digits are all different then 18. Otherwise, 192.
There are 900 of them.
15 of them.
27
Possible solutions - using your rules are:- 11,13,17,31,33,37,71,73 &77
6
There are 2000 such numbers.