"I offer my tributes to the great freedom fighter, scholar and thinker par excellence, Shri C Rajagopalachari on his birth anniversary," Modi tweeted.
Rajaji, also a former Home Minister in Pandit Jawaharlal Nehru's cabinet, "was known for his administrative and political skills as well as for his literary and cultural pursuits", the Prime Minister said.
"A remarkable personality!" he added.
Born in 1878, Rajagopalachari was the last Governor- General of India.