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. Also degrades 11- and 24-mers, but less efficiently. Directionality is controversial; shown to degrade 5-mers and less in a 3' to 5' direction (PubMed:22114320), and 11-mers in a 5' to 3' direction (PubMed:21087930). Converts 3'(2')-phosphoadenosine 5'-phosphate (PAP) to AMP. adenosine 3',5'-bisphosphate + H2O = AMP + phosphate Divalent metal cations; Co(2+), Mn(2+) or Mg(2+). Monomer or homodimer. In accordance with its dual activities, is able to complement both orn and cysQ mutants in E.coli. Belongs to the NrnA oligoribonuclease family. Truncated N-terminus.