How many neutrons are there in Hydrogen?

From 0 to 2.

Hydrogen has three natural isotopes. Hydrogen-1 – known as protium – doesn’t have any neutrons, and is the most abundant hydrogen isotope (99.985%). Hydrogen-2 has 1 neutron, and is called deuterium (D); its abundance amounts to only 0.015%. Hydrogen-3, or tritium (T), has 2 neutrons, is very rare and radioactive (source: “General, Organic and Biological Chemistry”).