Alright, let's work through 20490425 times 12658369 step by step
20490425 × 12658369 = 12658369 × (20490425)
+ 12658369 × 5 resulting in 63291845
+ 12658369 × 20 resulting in 253167380
+ 12658369 × 400 which equals 5063347600
+ 12658369 × 0000 giving us 0
+ 12658369 × 90000 which equals 1139253210000
+ 12658369 × 400000 giving us 5063347600000
+ 12658369 × 0000000 that equals 0
+ 12658369 × 20000000 giving us 253167380000000

= 259375360616825
