10027
This number is a composite.
The smallest five-digit composite number ending in 1, 3, 7 or 9 that yields no primes if the first digit is changed. I.e., 20027, 30027, 40027, 50027, 60027, 70027, 80027 and 90027 are all composite.
Printed from the PrimePages <t5k.org> © G. L. Honaker and Chris K. Caldwell