The "tout" in front makes autour an adverb rather than a preposition.
As a preposition, autour is always followed by "de" and a noun. Autour de (autour de la taille, autour de l'hôpital, autour du jardin)
With "tout" before the word it can function as an adverb to mean simply "around" or "all around." tout autour
Salut Louise616982. The use of “tout” in this instance is well explained in the discussion group posts by moderator Commeune Texane. In general, just like a French adjective, “tout” has male and female, singular and plural forms that must agree with the subject.
“Tout” = male singular “Tous” = male plural “Toute” = female singular “Toutes” = female plural
Hence “Tous les jours” (Male plural to agree with “jours”) = “all the days/ every day” “Toute a l’heure” (Female singular to agree with “heure”) = “See you very soon (typically in an hour or two)”