It is: 403 = CDIII
13*31=403 13 and 31 are prime numbers.
1, 5, 13, 31, 65, 155, 403, 2015
403
The GCF is 31.
403, 806, 1209, 1612 +403 . . .
1, 3, 9, 13, 31, 39, 93, 117, 279, 403, 1209, 3627.
Any of its factors which are 1, 13, 31 and itself 403
13 x 31
26, 62, 403, 806 are the composite factors of 806.
The LCM of the given prime numbers is 403
Two or more numbers are normally needed to find the GCF