Bifunctional enzyme which has both oligoribonuclease and pAp-phosphatase activities. Degrades RNA and DNA oligonucleotides with a length of 5 nucleotides and shorter, with a preference for longer oligomers. Converts 3'(2')-phosphoadenosine 5'-phosphate (PAP) to AMP (By similarity). adenosine 3',5'-bisphosphate + H2O = AMP + phosphate Probably essential, it was not disrupted in a global transposon mutagenesis study. Belongs to the NrnA oligoribonuclease family.