11
This number is a prime.
Just showing those entries submitted by 'Meller': (Click here to show all)
The smallest prime which when sandwiched between a two-digit repdigit gives a multiple of 11. In other words 1111, 2112, 3113, 4114, 5115, 6116, 7117, 8118, and 9119 are multiples of 11. [Meller]
Printed from the PrimePages <t5k.org> © G. L. Honaker and Chris K. Caldwell