(10^2000 - 1)(10^2000 - 1)
= 10^4000 - 2*10^2000 + 1 (99999...9998000...00001
各位数字之和是 9*2000 = 18000
=999..9(1998个9)8000..0(1998个0)1
个位数字之和=9×1998+8+0×1998+1=17991
=100.。。。0(1999个0)*999.。。9(1999个9)-999.。。。9(1999个9)
=999.。。。9(1998个9)8000。。。0(1998个0)1
积是999...980.....01(有1998个9 1998个0)
各个数位之和是17991