[Machine] The Prophet ﷺ had three muezzins: Bilal, Abu Mahdhurah, and Ibn Umm Maktum. Abu Bakr and Al-Khabbaran both stated that this is correct. Whoever says the Prophet ﷺ had two muezzins is referring to those who used to call for prayer in Madinah, while whoever says three is referring to Abu Mahdhurah, who used to call for prayer in Makkah. The scholar stated that the fact that Abu Mahdhurah was the only one calling for prayer in Makkah indicates that it is permissible to have only one muezzin.  

كَانَ لِلنَّبِيِّ ﷺ ثَلَاثَةُ مُؤَذِّنِينَ بِلَالٌ وَأَبُو مَحْذُورَةَ وَابْنُ أُمِّ مَكْتُومٍ قَالَ أَبُو بَكْرٍ وَالْخَبَرَانِ صَحِيحَانِ يَعْنِي هَذَا وَمَا تَقَدَّمَ فَمَنْ قَالَ كَانَ لَهُ مُؤَذِّنَانِ أَرَادَ اللَّذَيْنِ كَانَا يُؤَذِّنَانِ بِالْمَدِينَةِ وَمَنْ قَالَ ثَلَاثَةً أَرَادَ أَبَا مَحْذُورَةَ الَّذِي كَانَ يُؤَذِّنُ بِمَكَّةَ قَالَ الشَّيْخُ وَفِي اقْتِصَارِهِ بِمَكَّةَ عَلَى مُؤَذِّنٍ وَاحِدٍ دَلَالَةٌ عَلَى جَوَازِ الِاقْتِصَارِ عَلَى مُؤَذِّنٍ وَاحِدٍ