On Friday amid the fanfare of Donald Trump's inauguration, Barack Obama will become the 44th former president of the United States.

Unusually it will be the younger man making way for an elder successor, with Trump taking power aged 70, giving the 55-year-old Obama plenty of time to explore a new career path upon leaving the White House.

Having signalled his intention not to run for another political office, here's what is on the soon-to-be former president's to-do list:

"I've promised Michelle a nice vacation," Obama told America's National Public Radio last month, adding that the trip to an undeclared destination will mark the end of more than one chapter in his family's life.

"My girls are getting old enough now where I'm clinging to those very last moments before they are out of the house."

The Obamas will remain in Washington DC after leaving the White House, and will rent an 8,200-square-foot mansion in the Kalorama neighbourhood of the city.

The former president will trade down from the Oval Office into a personal office in the headquarters for the World Wildlife Fund and continue to earn around $200,000 (£166,000) a year as a former president.

Though he has the advantage of being a published author, Obama is expected to employ his chief White House speechwriter, Cody Keenan, to help him craft his eagerly anticipated presidential memoir.

The advance for Obama's third book (after 1995's Dreams From My Father and 2006's The Audacity Of Hope) is tipped to be in region of more than $20 million (£16.6 million) - the highest of any ex-president.

The promotional tour to support its release is expected in 2018.

Obama's presidential library and centre already has a location: it will be hosted by the University of Chicago in a park on his hometown city's South Side.

The nonprofit Barack Obama Foundation is charged with raising money for the institution, which could cost around half a billion dollars, and has an estimated completion date of 2020.

It will become the 14th site to house the archives and records of a former president.

Both Barack and outgoing first lady Michelle Obama have declined interest in pursuing political office but remain committed to public life and policy.

The soon-to-be-ex-president said he has ideas for how the Democrats can revive themselves in the wake of Hillary Clinton's failure to retain the White House but is unlikely to broadcast them.

But he has pledged to keep a low political profile - citing his predecessor George W Bush as inspiration - and will not offer a commentary on Donald Trump's performance unless the 45th president takes a particularly extreme course of action.

Ever popular with political leaders after leaving the corridors of power, Obama can expect to command inordinately high fees for his career-defining oratory skills on the global speech circuit.

Obama is also believed to have held meetings with leading Hollywood agent Ari Emanuel regarding the potential for him to harness digital media and television.

Whatever direction he takes, the natural performer is not expected to shy away from public life.

What have other ex-presidents done after leaving the White House?

America's first president George Washington made whisky, opening the country's then-largest distillery and producing 11,000 gallons of booze until his death in 1799.

Teddy Roosevelt embarked on a 1913 hunting expedition in Brazil but suffered malaria and an infected leg wound that he later claimed 'stole away 10 years of my life'.

The 27th US president William Taft reclaimed high office eight years after leaving the White House in 1913, becoming the 10th chief justice of the Supreme Court and declaring: "Presidents come and go, but the Supreme Court goes on forever." He remains the only person to hold both positions.

The often-maligned Jimmy Carter earned global praise for eradicating the guinea worm disease through his nonprofit Carter Center as global cases of the contaminated water disease fell from 3.5 million in 1986 to 22 in 2015.

George W Bush devoted himself to painting and has exhibited his portraits of world leaders, along with many depictions of his dogs.