To keep your belly button from smelling make sure to clean the belly button daily or every few days using some soap and water and also some hydrogen peroxide or apple cider vinegar.
The hydrogen peroxide or apple cider vinegar can help kill off bacteria that leads to a yeast infection which can make the belly button smell and make your belly button produce a white discharge and also a red itchy rash.
Most people forget to clean their belly button when showering but the belly button needs to be cleaned often to prevent dirt and other bacteria from building up.
Use some antibacterial soap often as well and use a Q Tip to help clean the belly button which will make it easier to clean.
You can also use some baking soda and vinegar to clean your belly button and it will help reduce the odors from the belly button.