Abu Hurairah (RA) said: The Messenger of Allah (ﷺ) instructed to recite this dhikr while leaving the mosque -

اَللَّهُمَّ أَجِرْنِيْ مِنَ الشَّيْطَانِ الرَّجِيمِ

Allaahumma, ajirni minash Shaytaanir rajeem

O Allah, protect me from Satan the outcast.

Reference: Sahih (Ibn Hibban). Ibn Hibban: 2047