16, with factors 1, 2, 4, 8 and 16.
Because they only have two factors, as do 17 and 19.
The only prime number between 5 and 10 is 7.
They are the numbers that have more than 2 factors in them because a prime number has only 2 factors which are itself and one
A number that has exactly an odd number of factors is a power of another number. A number between 10 and 30 that is a power is 16. It is 24 (as well as 42) and its factors are 1, 2, 4, 8, and 16.
48 has 10 factors.
12
1 is the only factor of 611 that is between 1 and 10.
10, which has the factors 1,2,5 and 10. If the trivial pair 1 and the number itself are disallowed, the answer is 12 with factors 2,3,4 and 6.
48
10
The only factors of 10 are 1, 2, 5, and 10.
The factors of 10 are 1, 2, 5, and 10. There's no such thing as the GCF of a single number, only of two or more.