6163

This number is a prime.

+ The smallest non-palindromic old-beast prime. Note that 6163, 61603, 616003, and 6160003 are all prime.

+ (6163, 6361) is the largest pair of primes formed from the concatenation in ascending and descending orders of two successive double-digit odd numbers. Can you find the two previous cases? [Loungrides]

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