Has nucleotide phosphatase activity towards ATP, GTP, CTP, TTP and UTP. Hydrolyzes nucleoside diphosphates with lower efficiency. a ribonucleoside 5'-triphosphate + H2O = a ribonucleoside 5'-diphosphate + H(+) + phosphate H2O + TTP = H(+) + phosphate + TDP CTP + H2O = CDP + H(+) + phosphate ATP + H2O = ADP + H(+) + phosphate GTP + H2O = GDP + H(+) + phosphate Monomer. Belongs to the THEP1 NTPase family.