It is not form OG but from what we have learned from math teather in high school.The validity of this fomula is guaranteed.You can put some values to test it.
According to the formula:
the number of factor of (a^x*b^y*c^z),where a,b,c are different prime factors,=(x+1)(y+1)(z+1)
Of course,a,b,c and x,y,z can expend to c,d,e…… to meet the different questions.
