4226
This number is a composite.
4226 = phi(4)^sigma(4) + phi(2)^sigma(2) + phi(2)^sigma(2) + phi(6)^sigma(6). Note that 4226 is the earliest multi-digit number with this property. [Firoozbakht]
Printed from the PrimePages <t5k.org> © G. L. Honaker and Chris K. Caldwell