7879
This number is a prime.
The first emirp encountered in the decimal expansion of
ii,
where i is the square root of -1. [Beedassy]
The smallest emirp formed from the last three digits. [Loungrides]
The larger prime in the largest twin prime pair (7877, 7879) formed by using three consecutive double-digit numbers, i.e., 77, 78, 79. [Loungrides]
Printed from the PrimePages <t5k.org> © G. L. Honaker and Chris K. Caldwell