Family name Retnakumar (Retnakumar 
) , in the world, is a very rare cognomen. The surname Retnakumar is habitual in Malaysia, where it is a rare surname, the United Kingdom, where it is an extremely rare surname, and India. Also, Retnakumar is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Retnakumar | United States, United Kingdom, India, Malaysia |