74773...54321 (222-digits)

This number is a probable-prime (likely to be a prime but we have not (re-)proven it on this site).

                                                               74 7737727717
7076966866 7666665664 6636626616 6065955855 7556555554 5535525515 5054944844
7446445444 4434424414 4043933833 7336335334 3333323313 3032922822 7226225224
2232222212 2021911811 7116115114 1131121111 1019988776 6554433221 1987654321

+ The largest non-titanic prime formed by concatenating in descending order the first n palindromic numbers (case n=83). [Gupta]

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