Is outie the same as umbilical hernia?

Most likely: Yes - when a belly button becomes an outie, it is likely the result of an umbilical hernia.

Almost always: Everyone is born with an umbilical hernia. It's where your mom's umbilical cord fed you before birth. Most floks hernia closes by age 3 to 4. Some folks whose defects don't close will have "an outie" and most of those are an umbilical hernia. Small umbiilcal hernias do not usually have to get repaired, but the natural history of hernias is that they will get larger and require eventual repair.

Not necessarily : Although I have found many small hernias that people thought were just 'outies'. For it to be a hernia there needs to be a defect in the muscle with bowel or fat coming through. Conversely, an outtie is usually just skin and scar.