720的约数共有几个?这些约数之和共多少?求详细过程!谢谢!

720=2*2*2*2*3*3*5720的约数有1,2,3,4,5,6,8,9,10,12,15,16,18,20,24,30,36,40.45,48,60,72,80,90,120,144,180,240,360,7201+2+3+4+5+6+8+9+10+12+15+16+18+20+24+30+36+40+45+48+60+72+80+90+120+144+180+240+360+7...