They also showered praises on Rajagopal for his "unsullied" public career of the last 50 years.
"The galaxy of leaders present here itself is a big tribute to Rajagopal. It is not words but the presence of the leaders and dignitaries that matters on an occasion like this," Advani said.
Stating that he would continue to oppose stiffly the ideology of Rajagopal's party, Achuthanandan said that he, however, respected the leader as a clean public figure whose career had never been tainted with corruption.
Achuthanandan also said Rajagopal had been able to make several contributions to the railway development of Kerala when he was minister at the Centre.
Congress leader and Kerala Transport Minister V S Sivakumar, CPI state secretary Panniyan Raveendran, Jnanpith laureate O N V Kurup, city Mayor K Chandrika and Bharatheeya Vicharakendram Director P Parameswaran were among those turned up to felicitate Rajagopal at the University Senate Hall here.