come si fa 256421 x 5490 ?

1 2 4 6 5 2 0 9 4 5 x = 0 0 0 0 0 0 9 8 1 7 3 7 5 0 5 3 2 4 8 6 1 5 2 2 2 0 1 5 0 1 1 2 2 3 8 2 2 1 1 2 1 1 0 9 2 1 5 7 7 0 4
x