1723

This number is a prime.

+ Proving the Riemann Hypothesis is equivalent to showing

floor(H(n)+eH(n))*log(H(n)) ≥ σ(n),
where H(n) = 1 + 1/2 + 1/3 + ... + 1/n, and σ(n) is the sum of the divisors of n. For example, when n = 17, the two sides differ by 23. [Caldwell]

+ The prime that splits into the two primes, 17 and 23, which are the extremal constants of the magic triangle of Yates using digits 1 through 9:

       1                 7 

     9   6             3   6 

   5       7         5       1 

 2   8   4   3     8   2   4   9
[Beedassy]

+ The smallest distinct-digit emirp concatenated from two double-digit primes. [Loungrides]

(There are 4 curios for this number that have not yet been approved by an editor.)

Printed from the PrimePages <primes.utm.edu> © G. L. Honaker and Chris K. Caldwell