UNITED NATIONS — When the 193-member United Nations convenes this week for the annual General Assembly speeches and high-level meetings, world leaders will be paying closest attention to the words and gestures of the most unconventional — and powerful — leader among them.

What President Trump says, whom he may offend, please or surprise and how other international leaders react at the world’s largest diplomatic gathering are topics that are likely to dominate the chatter at the United Nations, which, in its 72nd year, is barely older than Mr. Trump.

Here are five issues to watch:

The Trump effect

While this will be Mr. Trump’s first visit to the United Nations as president, he has castigated the organization as an elitist “club” and proposed what amount to drastic cuts in voluntary contributions from the United States, the single-biggest donor.