LeftTruncatablePrimeQ[n_] := Times @@ IntegerDigits[n] > 0 && And @@ PrimeQ /@ ToExpression /@ StringJoin /@ Rest[Most[NestList[Rest, #, Length[#]] &[Characters[ToString[n]]]]] RightTruncatablePrimeQ[n_] := Times @@ IntegerDigits[n] > 0 && And @@ PrimeQ /@ ToExpression /@ StringJoin /@ Rest[Most[NestList[Most, #, Length[#]] &[Characters[ToString[n]]]]]