He breathed his last at United Hospital around 11pm on Friday, his son Mashuque Alamgir Rajeeb said.
Known as a Gana Sangeet singer, later a pop artist, and his work with Swadhin Bangla Betar Kendra during the 1971 Liberation War, he won the Ekushey Padak, the second highest civilian award, in 1999.
President Md Abdul Hamid and Prime Minister Sheikh Hasina have led the nation in paying tribute to Alamgir.
They remembered the role he played in strengthening patriotism and the Liberation War spirit among the youth through his songs.
Hamid and Hasina also extended sympathy to his family and prayed for him.
Ghulam Quddus, president of Sammilita Sangskritik Jote, said funeral prayers for the singer will be held outside Pallima Sangsad in Khilgaon at 11am and at Khilgaon Matir Masjid after Zuhr prayers before the burial at Khilgaon Taltala Graveyard on Saturday.
The mortal remains of Alamgir will also be kept at the Central Shaheed Minar premises for all to pay respects by adhering to the health rules at 12pm.
Alamgir, who was fully vaccinated against the coronavirus, was diagnosed with the respiratory disease on Jul 14. He was hospitalised the next day due to breathing distress.
The doctors moved him to the Intensive Care Unit the same day, and then put him on life support on Jul 19 as his condition deteriorated.
His right lung improved but infection was detected in the left one on Friday. Doctors were also worried about infection in his blood. He finally suffered a cardiac arrest around 9:30pm.
Alamgir had been involved with Gana Sangeet, or the music of the masses, since the 1960s. He joined the 1969 mass uprising as a member of Kranti Shilpi Goshthi and Ganashilpi Goshthi.
When the Liberation War began, he joined Swadhin Bangla Betar Kendra, the radio station run by the Bangladesh government in exile.
After independence, he played a role in the development of pop music by fusing Western music with Bangladeshi folk music.
In his long career, he sang a number of popular songs. His song ‘O Sokhina’ is sung and crooned by millions.
Written by Altaf Ali Hasu and composed by Alamgir, the song became a household hit after he sang it in BTV’s ‘Anandamela’ show in 1982.
The founder of cultural organisation Wrishijo Shilpi Goshthi was a former president of Gana Sangeet Shilpi Parishad.
Alamgir did his post-graduation at Dhaka University’s mass communication and journalism department.
He also penned several books. They include ‘Muktijuddher Smrity O Bijoyer Gaan’, ‘Gana Sangeeter Oteet O Bartaman’, ‘Amar Kotha’, and ‘Jara Achhen Hridoy Pote’.