44444...11111 (274-digits)
This number is a probable-prime (likely to be a prime but we have not (re-)proven it on this site).
4444 4444444444 4444444444 4444444444 4444444444 4444444444 4444444444
4444444444 4444444444 4444444444 4444444444 4444444444 4444444444 4444444444
4444444444 4444444444 4444444440 0000000000 0000000000 0000000000 0000000000
0000000000 0000000000 0000000000 0000000001 1111111111 1111111111 1111111111
Delete only one digit from any number, and all are still
primes. Note that the first prime greater than a googol of
this type. [Marcel]
Printed from the PrimePages <t5k.org> © G. L. Honaker and Reginald McLean