5555
This number is a composite.
The sum of the 9th + 18th + 27th + ..... + 135th prime. [Bopardikar]
5555n + 162 is prime for n = 0 to 7. [Blanchette]
The decimal part of 55551/3 starts with the reversal of
its integer part (which happens to be an emirp), i.e., 17.71.... [De Geest]
The 2nd repdigit number consisting of 5’s whose the product
with all its truncations plus 2 is prime, i.e.,
5555*555*55*5+2=847831877. The previous such prime is
55*5+2=277 and the next is 55555555*5555555*…*5+2. [Loungrides]
Printed from the PrimePages <t5k.org> © G. L. Honaker and Chris K. Caldwell