The Obamas could earn more than $200 million in the next 15 years

Being president of the United States is perhaps the most powerful job on earth. And being a former-US president can be one of the most lucrative.

Between book deals, speaking engagements, and a government pension, former-President and First Lady Barack and Michelle Obama stand to earn as much as $242.5 million in the next 15 years, according to research from the Kogod School of Business at American University. Considering that the couple was worth around $1.3 million when they entered the White House, they're on track to substantially increase their net worth.

To calculate the Obamas' future earning potential, researchers focused primarily on what they're likely to gain from books and speeches, adding that number to the $200,000 annual pension the newly departed president will receive from the government.

"President Obama leaves office with two best-sellers already to his name to add to the estimated $40 million in book fees he and Michelle will receive," the study says. "Add $3 million in pension income and about 50 speeches a year at a conservative $200,000 apiece and you're already close to $200 million before taxes."

Barack wrote his first book, "Dreams from My Father: A Story of Race and Inheritance," in 1995, but it really took off in 2008 during his first run for president. He followed that with "The Audacity of Hope: Thoughts on Reclaiming the American Dream," released in 2006 while he was a senator.

Both Barack and Michelle are expected to release autobiographies based on their experiences in the White House, which could rake in between $20 million and $45 million for the couple, with the potential to become the most valuable presidential memoir of all time, according to the New York Times.

Speaking engagements also hold enormous potential for the Obamas. The study reports (via CNN) that Bill and Hillary Clinton have earned an average $210,795 per address they've given over the past 15 years since leaving the White House, so it follows that the Obamas could bring in the same, if not more.

But despite the Obamas' immense earning potential, their total wealth is still likely to be dwarfed by that of President Donald Trump, who stands as the richest president in US history by a long shot. Since Trump hasn't released his tax returns, his complete financial situation remains somewhat unclear, but he's nonetheless estimated to be a billionaire, with Forbes pegging his net worth at $3.7 billion.