You need at least two numbers before you can talk about common factors. 54 is only one number. As such, there is no real answer to your question. The factors of 54 are 1, 2, 3, 6, 9, 18, 27 and 54.
The common factors of 32 and 54 are: 1 and 2
The common factors of 54 and 75 are 1 and 3.
Common factors of 54 and 22 are: 1 and 2.
Since 54 is a factor of 108, all of 54's factors are common and the GCF is 54 itself.
The common factors of 54 and 63 are: 1, 3, and 9
The common factors of 45 and 54 are: 1, 3, and 9
Since 18 is a factor of 54, all of its factors are common.
The common factors of 6 and 54 are: 1, 2, 3, and 6
The common factors of 28 and 54 are: 1, 2
The common factors of 54 and 276 are 1, 2, 3, and 6
The common factors of 12 and 54 are 1, 2, 3, and 6.
Since 18 is a factor of 54, all of its factors are common.