"With deep sadness, we announce that our beloved Niki has peacefully passed away with his family on Monday," his family said in a statement.
"His unique achievements as an athlete and entrepreneur are and will remain unforgettable, his tireless zest for action, his straightforwardness and his courage remain.
"A role model and a benchmark for all of us, he was a loving and caring husband, father and grandfather away from the public, and he will be missed."