3407
This number is a prime.
(3407, 7043) is the only pair of 4-digit distinct-digit
emirps whose one digit is equal to the sum of the other
digits. [Loungrides]
An emirp whose sum of two leftmost digits is equal to the sum of its two rightmost digits. [Forouhari]
(There is one curio for this number that has not yet been approved by an editor.)
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