7297

This number is a prime.

+ The diagonals of a regular 24-gon intersect at 7297 internal points (6144 intersections of two diagonals, 864 of three, 264 of four, 24 of five, and one intersection of twelve diagonals). [Caldwell]

+ The smallest emirp that remains an emirp when each digit is repeated a number of times equal to its complement: 777222222229777. [Beedassy]

(There is one curio for this number that has not yet been approved by an editor.)

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