55555555
This number is a composite.
The product of this repdigit number consisting of eight 5’s with all its truncations plus 2 is the largest non-titanic prime with this property, i.e., 55555555*5555555*555555*55555*5555*555*55*5+2 =
8076345598969038563182858894921877. [Loungrides]
Printed from the PrimePages <t5k.org> © G. L. Honaker and Chris K. Caldwell