Allen died from complications of non-Hodgkin lymphoma, his private company Vulcan Inc. said Monday on behalf of his family.
Allen revealed that he had started treatment for non-Hodgkin lymphoma earlier this month having overcome the cancer nine years earlier.
He had left Microsoft when he was first diagnosed with the disease.
Allen was ranked among the world’s wealthiest individuals having ranked 44th on Forbes’ 2018 list of billionaires.
Allen’s sister Jody praised her brother in an emotional statement.
“While most knew Paul Allen as a technologist and philanthropist, for us he was a much-loved brother and uncle, and an exceptional friend,” Jody said in a statement.
“Paul’s family and friends were blessed to experience his wit, warmth, his generosity and deep concern.
“For all the demands on his schedule, there was always time for family and friends.
“At this time of loss and grief for us – and so many others – we are profoundly grateful for the care and concern he demonstrated every day.”
Current Microsoft CEO Satya Nadella added: “Paul Allen’s contributions to our company, our industry and to our community are indispensable.
“As co-founder of Microsoft, in his own quiet and persistent way, he created magical products, experiences and institutions, and in doing so, he changed the world.”
Current Seahawks player continued the tributes.
Wide receiver Tyler Lockett posted on social media: “Rest In Peace Paul Allen. Thank you for everything! You will be missed. My prayers go to the entire Allen family.”
Offensive tackle Duane Brown added: “RIP Paul Allen. Gone way too soon. Thank you so much for your many contributions to society and to the sports world.”
Since taking over Portland Trail Blazers, the side reached the NBA playoffs 19 times including the NBA Finals in 1990 and 1992.