780的偶约数有几个?奇约数有几个?
问题描述:
780的偶约数有几个?奇约数有几个?
答
780=1*2*2*3*5*13奇约数:1,3,5,13,15,39,65,195共8个
偶约数:2,4,6,10,26,30,60,78,130,780,390,52,20,156,260,12共16个