This number is a composite.
Just showing those entries submitted by 'Rivera': (Click here to show all)
843753 x 222222 ± 1 is a 6696-digit twin prime pair found by Rivera and Gallot in 1997. It was the first time that a twin prime found using Proth.exe by a solitaire prime-hunter hit the Top Ten Table of twin-primes (2nd place), compiled by C. Caldwell. [Rivera]