1998=2x3x3x3x37=2x3^3x37
S=[(2^2-1)/(2-1)][(3^4-1)/(3-1)][(37^2-1)/(37-1)]
=[(4-1)/(2-1)][(81-1)/(3-1)][(1369-1)/(37-1)]
=[3/1][80/2][1368/36]
=3*40*38
=120*38
=4560
16200=2x2x2x3x3x3x3x5x5=2^3*3^4*5^2
S=[(2^4-1)/(2-1)][(3^5-1)/(3-1)][(5^3-1)/(5-1)]
=[(16-1)/(2-1)][(243-1)/(3-1)][(125-1)/(5-1)]
=[15/1][242/2][124/4]
=15*121*31
=1815*31
=56265