In the Quran, Hazrat Muhammad (PBUH) was not called Abdullah. In that verse, the Prophet (peace and blessings of Allaah be upon him) is meant to be 'the slave of Allaah'. وَأَنَّهُ⁇ لَمَّا قَامَ عَبْدُ اللَّهِ يَدْعُوهُ كَادُوا يَكُونُونَ عَلَيْهِ لِبَدًاAnd when the servant of Allah stood up to call upon Him , they gathered around him. In verse 19 of Surah Al-Jinnعَبْدُ اللهِ The Prophet (peace and blessings of Allaah be upon him) was meant to be a servant of Allaah.