Surname Radaikin (Radaikin 
, Радаикин , Радайкин 
) , in the world, is a rare cognomen. The last name Radaikin is habitual in Russia, where it is a rare surname, Kazakhstan, and Kyrgyzstan.
| VARIANT | COUNTRY |
|---|---|
| Radaikin | United States, Russia |
| Радаикин | Russia |
| Радайкин | Kazakhstan, Kyrgyzstan, Russia |