This number is a prime.

+ The only near-repdigit prime ending with 1 that contains d times the digit d. [Loungrides]

+ The largest known prime p such that p-t are all composite for p/2 < t < p, where t is a triangular number. [Capelle]

+ First prime obtained from another prime (31) repeating k times each digit k. [Leonardis]

(There are 6 curios for this number that have not yet been approved by an editor.)

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