1487
This number is a prime.
The first prime which requires 9 steps in the reverse-and-add process to reach a palindrome. [Porter]
1487 and its reversal 7841 is the first distinct-digit pair
of emirps that are both super-2 primes, i.e., 2*1487^2 =
4422338 and 2*7841^2 = 122962562. [Loungrides]
(There is one curio for this number that has not yet been approved by an editor.)
Printed from the PrimePages <t5k.org> © G. L. Honaker and Chris K. Caldwell