2,199,999,999,978 & 4,399,999,999,956 & 8,799,999,999,912

[Math.] 

(*)   8712 = 2178×4 & 8712×2178 = 18,974,736 = 43562

87128712 = 21782178×4 & 87128712×21782178 = 435643562

 

(**)   87912 = 21978×4 & 21978×87912 = 1,932,129,936 = 439562

8791287912 = 21978…21978×4 & 21978…21978×87912…87912 = 43956…439562

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(***)   8,799,999,999,912 = 2,199,999,999,978×4 & 

2,199,999,999,978×8,799,999,999,912 = 4,399,999,999,9562

8799...99128799...9912 = 2199...99782199...9978×4 &

2199...99782199...9978×8799...99128799...9912 = 4399...99564399...99562

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(****)   879…912 = 219…978×4 & 219…978×879…912 = 439…9562

879…912879…912 = 219…978…219…978×4 &

219…978219…978×879...912…879...912 = 439…956439…9562.

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