29
This number is a prime.
Just showing those entries submitted by 'Firoozbakht': (Click here to show all)
29 is only known number m such that both m!-Rm and m!+Rm are primes. I.e., 29! - 111...1 (29 ones) and 29! + 111...1 (29 ones) are both primes. [Firoozbakht]
π(29) = phi(29) - 2*9. [Firoozbakht]
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