4226
This number is a composite.
Just showing those entries submitted by 'Firoozbakht': (Click here to show all)
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]
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