| Atomic Mass | Mass Excess |
| 138.906646727815 amu | -86.958 MeV |
| Level energy (MeV) | Spin & parity | Half-life | Mode of decay | Branch ratio (%) | Decay energy (MeV) |
| Ground state | 3/2+ | 137.640 D 0.023 | EC | 100 | .278 |
| .754 | 11/2- | 56.54 S 0.13 | IT | 100 | .754 |
| Decay mode | Half-life | Gamma-ray energy (keV) | Intensity (%) |
| EC | 137.640 D 0.023 | 165.853 | 79.886+-0.015 |
| IT | 56.54 S 0.13 | 754.24 | 92.45 |