No problem, we've got 78091875 and 21049025 to multiply
78091875 × 21049025 = 21049025 × (78091875)
+ 21049025 × 5 that is equal 105245125
+ 21049025 × 70 what gives us 1473431750
+ 21049025 × 800 giving us 16839220000
+ 21049025 × 1000 giving us 21049025000
+ 21049025 × 90000 which equals 1894412250000
+ 21049025 × 000000 producing 0
+ 21049025 × 8000000 producing 168392200000000
+ 21049025 × 70000000 that results in 1473431750000000

= 1643757829171875
