38

This number is a composite.

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Let spf = sum of prime factors (where spf(p) = 0); then spf(38) = 21, spf(21) = 10, spf(10) = 7, and spf(7) = 0. Note that 21 + 10 + 7 + 0 = 38. The numbers 20 and 74 also share this property. [Moseley]