Assuming the last word in the question is "first" rather than "fist", all of them: 16, 27, 38 and 49 are all composite.
1346
There is no three digit prime number whose square root is a prime number. Prime numbers have no factors other than 1 and themselves. Any number having a prime number as a square root is a composite number.
84
The number is 9376.
33, 63 and 93
123
It is composite, as are all whole numbers whose last digits are even.
36
930
36
The largest 3 digit number whose digits are all primes is 777. The largest 3 digit number with different prime digits is 753.
67