3 times
أَعُوذُ بِاللَّهِ مِنَ الشَّيطَانِ الرَّجِيمِ، وَاتْفُلْ عَلَى يَسَارِكَ (ثلاثاً)
Meaning
othman Ibn Al-AAas narrated: I said ‘O Messenger of Allah, verily the devil comes between me and my prayer and recitation making me confused’ The Messenger of Allah replied ‘That is a devil called Khanzab, so if you sense his presence then seek refuge in Allah from him and spit (A form of spitting comprising mainly of air with little spittle) on your left side three times.
Source and references
Hisn al-Muslim, entry 138.The reference is copied from the edition; separate editorial verification is not complete yet.
Source edition: Fortress of the Muslim. Open source ↗