WASHINGTON — The pen has never been mightier. President Donald Trump’s Sharpie pen, that is.

Mr. Trump’s suspected use of a signature black Sharpie to alter a hurricane map has prompted thousands of mocking tweets, late-night comedy jokes and a viral internet meme. It has also further fused a staple of American homes and offices with the image of a highly divisive president, showing that even a humdrum marker maker can be swept up in the constant furor surrounding the Trump White House.

Mr. Trump is a longtime user of the Sharpie pen, whose thick, bold imprint is a visual reflection of Mr. Trump’s blunt — some might say crude — style. Well before he was president, he regularly used the pens to sign autographs, write notes and mark up printed news articles before sending them back to their authors.

As president, Mr. Trump appears more enamored of the pens than ever, using them to sign his name to proclamations and legislation in his distinctive EKG-style signature. He has even had the company custom design a presidential version of its iconic pen, emblazoned with his signature, for his official use.

The free publicity Sharpie has enjoyed during the Trump era, and especially in the day since the appearance of the altered hurricane map, is almost impossible to calculate. But that attention has taken on a different tone this week, with some Trump critics even calling (perhaps jokingly) for a boycott of the pen maker, which is owned by the conglomerate Newell Brands.