145

This number is a composite.

+ The 145th prime number is 829 and 145829 is prime. Note that 1 + 4 + 5 + 8 + 2 + 9 is the largest prime factor of 145. Note also that 145 is congruent to 1 mod(8, 2, 9) and (8! + 2! + 9!) - (1! + 4! + 5!) is prime. [Petersen]

+ 145 = 1! + 4! + 5! = 5 x 29 and is the smallest semiprime with this property. [Bajpai]

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

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