How long is a day on the sun?

How long is a day on the sun? At first might seem like a stupid question. A day is how long it takes the sun to come back overhead. Doesn’t happen on the sun, unless you’re standing upside down, in which case days on the sun are infinitesimally short and your hair is on fire. But maybe a day is how long it takes to spin around relative to the distant stars, in which case different parts of the sun have different days because it’s a big ball of flowing, gassy plasma and different parts rotate at