Family name ฤทธิจักร (Power 
, ฤทธิจักร 
, Rittijak ) , in the world, is a common cognomen. The family name ฤทธิจักร is characteristic of Ireland, where it is a common surname, Guernsey, where it is quite a common surname, and Australia (explore the name in all countries). In absolute terms, it is the most numerous in the United States, the United Kingdom, and Canada. Much less frequently, ฤทธิจักร is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Power | United Kingdom, United States, Ireland, Australia, Canada |
| ฤทธิจักร, Rithijak, Rittijak | Thailand |
Ridthijak, Ritthichak, and Ritthijak