Catalyzes the hydrolysis of ribonucleotide and deoxyribonucleotide monophosphates, releasing inorganic phosphate and the corresponding nucleoside (PubMed:11133996, PubMed:34814800, PubMed:7599155, PubMed:8967393). AMP is the major substrate but can also hydrolyze dCMP and IMP (PubMed:11133996, PubMed:34814800, PubMed:7599155, PubMed:8967393). {ECO:0000269|PubMed:11133996, ECO:0000269|PubMed:34814800, ECO:0000269|PubMed:7599155, ECO:0000269|PubMed:8967393}. This is the function of NT5C1A (5'-nucleotidase, cytosolic IA, Ensembl gene identifier ENSG00000116981).