Proper factors are just like regular factors, except they don't include 1 and the number itself.
No. Some proper factors are prime.
No, no prime number has proper factors.
1 doesn't have proper factors.
One has no proper factors.
The proper factors of 26 are 2 and 13
The proper factors of 35 are 5 and 7.
Prime numbers don't have proper factors.
Prime numbers don't have proper factors.
Prime numbers don't have proper factors.
The proper factors of 220 are 2,4,5,10,11,20,22,44,55,110
The proper factors of 22 are 2 and 11.
Prime numbers don't have proper factors.