This number is a prime.

                                                   111 1111111111 1111111117

+ This near-repunit prime can be written as R23+6, where R stands for the nth repunit. It and R23 are in fact the largest known cases of a single group of ten numbers from (1)w0 to (1)w9 containing more than one prime.

+ The smallest near-repunit prime containing p times the smallest repunit prime p. [Beedassy]

+ 11111111111111111111111 is a unique happy prime, but unfortunately, 11111111111111111111117 is its unhappy sexy neighbor! [Green]

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