The grandiose reception seeks to convince Mr. Trump that his priorities are theirs, too, and that they are indispensable partners in fighting terrorism, in confronting Iran, in bolstering American businesses and perhaps even in pursuing peace between Israelis and Palestinians.
“It is a remarkably buoyant moment for them,” said Stephen A. Seche, a former United States ambassador to Yemen and the executive vice president of the Arab Gulf States Institute in Washington. “They want to reinforce the idea that there is a strategic partnership, that their interests and ours are closely aligned.”
The number of events scheduled throughout the Saudi capital, Riyadh, on Saturday and Sunday is staggering, as the Saudis seek to project their country as a dynamic one, a leader in the Arab and Islamic worlds and a close ally of the United States.
The stars and stripes are flying in Riyadh’s streets, intermixed with Saudi flags.
There are three summit meetings planned: between Mr. Trump and King Salman, the Saudi monarch; between Mr. Trump and the leaders of Persian Gulf states; and between Mr. Trump and more than 50 leaders and representatives from across the Muslim world.
Mr. Trump and King Salman will also inaugurate the Global Center for Combating Extremist Ideology, where Mr. Trump is to give a speech about Islam. The American president, a prolific — and often contentious — user of Twitter, will also deliver the keynote address at a conference about social media, under the auspices of Deputy Crown Prince Mohammed bin Salman, the king’s powerful son.
Elsewhere in the city, there is to be an international counterterrorism conference, a forum for chief executives and an art exhibition inside the Royal Court.
The exuberant reception for Mr. Trump reflects how differently Persian Gulf leaders see him compared with how they saw Mr. Obama.
Many of Mr. Obama’s Middle East policies angered the Saudis, including what they saw as his giving up on President Hosni Mubarak of Egypt, a longtime American ally, during the Arab Spring protests; his hesitation to intervene directly in the Syria conflict; and his pursuit of a nuclear deal with Iran, the Saudis’ regional nemesis.
The distaste for Mr. Obama grew so strong that when he visited the kingdom last year, only a small delegation met him at the airport and state television did not broadcast his arrival.
In Mr. Trump, however, many Saudis see a decisive, business-focused leader, who they say shares their goals in the region.
They applauded his military strike on a Syrian air base after President Bashar al-Assad’s forces used chemical weapons, and they have noted Mr. Trump’s tough talk on Iran. They hope he will increase support for the Saudi-led military campaign in Yemen against rebels — aligned with Iran — who have seized the capital, Sana. And they see a role for American investment in efforts to shift the Saudi economy from its dependence on oil.
“This administration is very clear, not just with Saudi Arabia, but also with Turkey and other traditional allies, that the idea is to double down on existing relationships and to put allies first,” said Mohammed Alyahya, a Saudi political analyst and nonresident fellow at The Atlantic Council, a policy research organization.
The Saudis have also pitched themselves as a Muslim ally against the jihadists of the Islamic State, and Mr. Trump’s desire to moderate his stance on Islam was among the reasons he chose Riyadh as his first foreign destination, according to administration officials.
The Saudis have spent a fortune on American weapons over the years, and a series of new deals that could be worth more than $300 billion over the next decade are close to completion, Reuters reported this month.
Mr. Trump also hopes Arab states like Saudi Arabia can play a role in brokering a deal between Israel and the Palestinians — an idea some Persian Gulf leaders have privately entertained, if Israel were to offer certain concessions.
Some aspects of Mr. Trump’s tenure that have caused criticism in the United States do not seem to bother the Saudis.
His reliance for policy advice on his daughter, Ivanka, and on her husband, Jared Kushner — both of whom will join him in Riyadh — is business as usual in a monarchy where princes run the government and the king has appointed one son as defense minister and another as ambassador to Washington.
And worries that Mr. Trump could use his presidency to benefit Trump hotels and golf courses get little traction in a country that is named after its royal family, and where the line between public and private wealth is vague.
Mr. Trump’s apparent lack of interest in human rights also suggests that he is unlikely to complain about the Saudi justice system or the limited rights of Saudi women.
Also invited to Riyadh is President Omar Hassan al-Bashir of Sudan, who has been indicted by the International Criminal Court for crimes including genocide, although it remains unclear whether he will attend or, if he does, whether he will meet Mr. Trump.
Because of their decades-old alliance, Saudi Arabia relies heavily on the United States for security and other issues. To maintain that alliance under Mr. Trump, Saudi leaders have studiously ignored his negative statements about Islam while emphasizing what their kingdom provides, including intelligence cooperation and billions of dollars in arms purchases.
Trump has not always returned the love.
“I think Islam hates us,” he said in an interview with Anderson Cooper of CNN last year. “There’s a tremendous hatred there.”
Last month, he told Reuters that protecting Saudi Arabia cost too much.
“Frankly, Saudi Arabia has not treated us fairly, because we are losing a tremendous amount of money in defending Saudi Arabia,” he said.
While such comments made some Saudis uncomfortable, they took heart from his ordering of a military strike in Syria — a step that Mr. Obama had declined to take — and they hope his tough talk on Iran will lead to action.
“When it comes to United States foreign policy, we have learned in this region that actions speak louder than words,” said Faisal J. Abbas, editor in chief of Arab News, a Saudi newspaper.
It remains unclear whether Mr. Trump’s visit will result in any concrete initiatives or will remain symbolic.
But some caution that what Mr. Trump will ultimately give Persian Gulf states may fall short of their great expectations.
“You have a Trump administration that has a banner of ‘American First’ and is preparing a counterterrorism strategy that seeks to place the burden more so on the shoulders of our partners,” said Brian Katulis, a senior fellow at the Center for American Progress, a Washington-based research organization, who has recently met with senior Persian Gulf officials. “Therein lies a potential for a mismatch of expectations.”