Simplify the following text for a Grade 6 native English-speaking person.
Original: Sanrio 's best known character is Hello Kitty , a white cat with red bow and no visible mouth , one of the most successful marketing brands in the world .
Simplified: Sanrio 's best known character is Hello Kitty , a white cat with red bow and no mouth . Hello Kitty is one of the most successful marketing brands in the world .