That is a big milestone for ex-kings in Nepal. Being 75 is huge because, no other kings in Nepal had been that old.
According to the historical record in Wikipedia, Rajendra Bikram Shah lived the most in the past. He died at the age of 68.

Gyanendra was born on 7 July 1947 as the second official son of King Mahendra. He reigned as the King of Nepal from 2001 to 2008. As a child, he was briefly ascended the throne to become the king from 1950 to 1951, when his grandfather, Tribhuvan, went on exile in India with the rest of his family.

His second reign began after King Birendra and his family were killed in the 2001 Nepalese royal Massacre. But, he was deposed by the first session of the Constituent Assembly on 28 May 2008, thereby declaring the nation as the Federal Democratic Republic of Nepal and abolishing the 240-year reign of the Shah Dynasty.

Early life

Gyanendra was born in the Narayanhiti Royal Palace, Kathmandu, as the second son of then Crown Prince Mahendra from his first wife, Crown Princess Indra Rajya Laxmi Shah. According to report, after his birth King Mahendra was told by a royal astrologer to stay away from his newborn son. The astrologer had told that Gyanendra can bring Mahendra bad luck. That is told to be the reason Gyanendra was sent to live with his maternal-grandmother. That was the reason he was left in Nepal when all the royal family members of King Tribhuwan went to India in November of 1950. King Tribhuwan took his father, Prince Mahendra and all other royal family members with him when he fled to India, leaving the young Prince Gyanendra, the only male member of the royal family in Nepal.

The Rana prime minister Mohan Shamsher brought him to the capital Kathmandu and declared him the King on 7 November 1950. Gyanendra was crowned and coins were also issued under his name. The Rana Prime Minister approved an annual budget for the king as Rs. 300,000. India and other foreign countries refused to accept Gyanendra as the king of Nepal. Later, in January 1951, when King Tribhuwan and Rana Prime Minister reached to an agreement Tribhuvan returned to Nepal and resumed the throne.

Gyanendra and his his elder brother Birendra went to St. Joseph’s School, Darjeeling, India for schooling. Gyanendra graduated from Tribhuvan University, Kathmandu in 1966. He also served as the chairman of the Advisory Committee for the Coronation of his brother King Birendra in 1975.

On May 1, 1970 Gyanendra married his second cousin Komal Rajya Lakhsmi Devi. Their first child, Prince Paras Bir Bikram Shah Dev was born on 30 December 1971. His sister Princess Prerana Rajya Lakshmi Devi Singh was born on 20 February 1978.

Happy 75th birthday to ex-king Gyanendra Shah.