Yes.
If the serial number is SP25002; 1973
It can be. Two is a factor of all even numbers.
Since two is a factor of all even numbers, it is a factor of 42.
A number that is a factor of two or more numbers is simply a common factor
A factor that two or more numbers share is known as a common factor.
All even numbers have two as a factor. Any two even numbers have (at the least) two as a common factor. That means the GCF of any two even numbers will have two as a factor. Any number that has two as a factor is even.
The factor of two plus two is four.
Two is a factor of all even numbers.
That would be called a "common factor" of the two (or more) numbers.
A whole number that is a factor of two or more numbers is a common factor.
The HCF is always a factor of the LCM of two numbers. The HCF is a factor of both the numbers which are factors of their LCM. Thus the HCF is also a factor of the LCM of the two numbers.
That's the greatest common factor, or GCF.