6247
This number is a prime.
The smallest prime which is sum of composite numbers written with the first primes repeated twice for each term, i.e., 6247 = 22 + 33 + 55 + 77 + 1111 + 1313 + 1717 + 1919. [Capelle]
(There is one curio for this number that has not yet been approved by an editor.)
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