Donald J. Trump was trumped.

The real estate mogul and Republican presidential candidate’s cellphone number was published Monday by the website Gawker.

It was a version of a prank Mr. Trump pulled recently on Senator Lindsey Graham of South Carolina, when Mr. Trump held aloft Mr. Graham’s cellphone number, scrawled on an index card, during a campaign appearance and urged people to do call him.

Gawker, which has had its own controversies for disclosing personal information of late, printed Mr. Trump’s number in an item under the headline, “Call Donald Trump’s Cell Phone and Ask Him About His Important Ideas.”

At the same time, The Associated Press reported that Mr. Trump’s company website had been the victim of a hacker, who posted an advertisement for Comedy Central’s “Daily Show” on the site.

A spokesman for Mr. Trump said he “has many private cellphone numbers, and the posting of this number does not effect him at all.”