This number is a composite.
Phi(63) = 36. [McCranie]
63 is the smallest number that can be expressed with 3 identical odd prime digits: 63 = 333 in base 4. [Necula]
π(63) = 6*3. [Kumar]
63^63-220 is the only positive non-titanic prime of form n^n minus the smallest amicable number. [Loungrides]
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