821
(another Prime Pages' Curiosity)
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+ The smallest prime of the first prime quadruple for which the sums of the cubes of the digits of the four primes (821, 823, 827, 829) are primes themselves (521, 547, 863, 1249). [Trotter]

+ The smallest prime whose reversal is a seventh power (128 = 27). [Gupta]

+ 6! + 5! - 4! + 3! - 2! + 1!. [Lownsdale]

+ The smallest of the prime quadruplet which is the largest of the three 3-digit prime quadruplets (101, 103, 107, 109}, {191, 193, 197, 199} and {821, 823, 827, 829} has, as digital reversal, the number of 6-digit prime quadruplets (128). [Post]




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