63

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]

(There is one curio for this number that has not yet been approved by an editor.)

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