What do an actor who co-starred with a chimpanzee; a peanut-farmer-slash-nuclear-physicist; and a hat salesman have in common?

All three were presidents of the United States of America.

When Donald Trump was sworn in as the 45th president of the United States, he was unusual in (at least) one respect: He had never before held elected office. But in many other ways, Trump is not very different from other presidents who have governed the country.

From college education to experience in politics, here's how Trump compares to past presidents. [The 15 Weirdest Inaugurations in History]

Older, white men

In one sense, Trump continues a historical precedent for presidents.

"They've all been men, and with the exception of Barack Obama, they were all white," said James Melcher, a historian at the University of Maine at Farmington.

Regarding religion, other than John F. Kennedy, who was Catholic, and Howard Taft, who was a non-Trinitarian Christian from the Unitarian sect, all of the presidents have been Protestant, Melcher added.

"We haven't had any Jewish presidents or avowedly nonbelieving presidents," Melcher told Live Science.

Trump, at age 70, was also the oldest person to be elected president. The next runner-up was Ronald Reagan, who was elected at age 69. The average age of presidents at first election is 54, while the youngest, Theodore Roosevelt, was elected at just 42. In the harder times of yesteryear, many of the past presidents never lived to reach Trump's age, Melcher said. The average life expectancy for men today is 78, but was only 57 in 1929, according to the Centers for Disease Control and Prevention.

Diverse educational backgrounds

In recent history, all U.S. presidents have had some college education, and four had some graduate-level education as well: President Bill Clinton has a law degree; George W. Bush has an MBA from Harvard Business School; and Barack Obama has a degree from Harvard Law School. So Trump's MBA from The Wharton School of the University of Pennsylvania makes him pretty average for a recent POTUS.

"The trend is toward more and more education, but not necessarily from Ivy League schools," Melcher told Live Science. "That's a real contrast to, say, the Supreme Court, where everybody on the Supreme Court attended Harvard, Yale or Columbia."

For instance, Reagan attended Eureka College in Illinois, Jimmy Carter attended the U.S. Naval Academy and Lyndon Johnson went to Southwest State Texas Teachers College (Now Texas State University).

Still, the Ivies are overrepresented in the yearbook of presidents: Seven U.S. presidents attended Harvard, and five went to Yale.

But a college degree hasn't even been a prerequisite for the highest office in the country; Harry Truman didn't have a college degree. Neither did George Washington. All told, eight presidents have had no education beyond high school, Live Science previously reported. (Four others enrolled in college but did not complete their degree.)

Professional experience

Of the past presidents, 26 have held a law degree, and eight have been teachers. In the mix, America has also been headed by a former model (Gerald Ford), an actor (Reagan), a peanut farmer (Jimmy Carter, who also happened to be a nuclear physicist on the side) and a mining engineer (Herbert Hoover). The country has also had its share of military men, from those who served in the army as enlisted men either at home or abroad (Carter and Reagan), to five-star generals (Dwight D. Eisenhower), according to WhiteHouse.gov.

A few, such as Truman, dabbled in business before embarking on a political career. Truman ran an unsuccessful business as a haberdasher, or hat maker, after World War I, Melcher said. George H.W. Bush was a successful oilman, becoming a millionaire before pursuing a political career. George W. Bush owned the Texas Rangers baseball team.

However, in at least one respect, Trump is unique: his complete lack of experience in elected office.

"Almost every president had been elected to something, or had been people who'd been serving in government," Melcher said. (Hoover was secretary of commerce before he was the Republican presidential nominee, but he had never been elected to any office.)

Trump's business experience, on the other hand, is much more extensive than past presidents', Melcher added.

Scandals

Though Trump's campaign and transition have been scandal-ridden, U.S. presidents are no strangers to such affairs, Melcher said. From Nixon's criminal dealings in Watergate, to the Iran Contra Affair under Reagan's tenure, to the bribery incident involving the Teapot Dome oil field under Warren G. Harding, presidents often find themselves in the hot seat for actions taken while they are president.

This election season, Trump was trailed by a cloud of sexual scandals. However, past presidents were also accused of sexual misdeeds. Clinton was sued by Paula Jones for sexual harassment, and was impeached under charges of lying under oath about his affair with intern Monica Lewinsky. Kennedy was a known philanderer, and Franklin Delano Roosevelt was said to have had multiple affairs. And rumor had it that Grover Cleveland fathered an illegitimate child, Melcher said. But in those times (with the exception of the Clinton scandal), the media mostly swept those stories under the rug, or deemed them not relevant to public office.

"The media used to be much less aggressive, rooting everything negative out," Melcher said.

However, it is unusual for someone to come into office on Inauguration Day with so many scandals brewing in so many different domains, Melcher said.

Trump recently settled a civil suit for $25 million alleging that he defrauded people who attended Trump University, according to the New York Times. He is currently being sued by a former cast member of "The Apprentice" reality show for defamation, after he claimed her sexual assault allegations were untrue, according to ABC News. Trump has been caught on video making comments describing sexual assault, and about a dozen women have come forward to say that he assaulted or harassed them.

And then there are the allegations that the Russians might have interfered with the election, including an unconfirmed intelligence report alleging that the Russians may be holding compromising information over him, according to the New York Times.

While allegations of foreign influence go back to the country's founding (Jefferson famously insinuated that John Adams was in the pocket of the British, while Adams claimed Jefferson was unduly influenced by the French), accusations of such overt meddling in politics by a foreign power is unusual, Melcher said.

"For all we know, Trump didn't know anything about it, but any move he makes that seems to be sympathetic to Russia, they'll say, 'You're doing that because the Russians have goods on you.' It makes for an awkward position for him in dealing with foreign affairs."

Originally published on Live Science.