What was the number on Gerald's shirt in "Hey Arnold!"?

The number on Gerald's shirt in "Hey Arnold" was 33. This number holds significance in the show as it represents a special number for Gerald, who is Arnold's best friend. It is commonly worn on his shirt as a way to symbolize friendship, loyalty, and unity. Additionally, the number 33 may also serve as a reference to the jersey number of a famous athlete or simply be a favorite number of the character's creator. Overall, the number 33 on Gerald's shirt is a recognizable and memorable aspect of his character design.