All whole numbers yes
One is a factor of all nonzero numbers.
One.
no
one
One is.
One.
Yes. One is a factor of all numbers.
1 is a factor of all positive numbers.
Yes, all number with have the factor 1 and itself.
No, all even numbers share one factor. The one factor being 2.
One of the numbers is a factor of the other.
All numbers have a common factor of 1. Sometimes that's the only common factor.