Mediates extracellular nucleotide derived phosphate hydrolysis along with NPP1 and PHO5. Hydrolytically removes 5'-nucleotides successively from the 3'-hydroxy termini of 3'-hydroxy-terminated oligonucleotides. a ribonucleoside 5'-triphosphate + H2O = a ribonucleoside 5'-phosphate + diphosphate + H(+) a 2'-deoxyribonucleoside 5'-triphosphate + H2O = a 2'-deoxyribonucleoside 5'-phosphate + diphosphate + H(+) Up-regulated during phosphate starvation. Autophosphorylated as part of the catalytic cycle of phosphodiesterase/pyrophosphatase activity. Belongs to the nucleotide pyrophosphatase/phosphodiesterase family.