47-521 is a male anthropomorphic dog.
A cousin of the Duckburg trio of Beagle Boys, 47-521, who resembles a thinner version of them, hadn't been seen by the Trio in about "five to ten years, with time off for good behavior" when he came to visit them upon learning they had taken control of Scrooge McDuck's fortune. He warned them that he was far from the only Beagle relative come to get a piece of the pie. Curiously, on this occasion, the number he wore on his chest was 45-521, even though he continued to be called 47-521 by his cousins without him objecting.
Behind the scenes
47-521 appears in the 1975 comic story Scrooge For A Day.