Well, the Hijri date 21 Shawwal 1187 corresponds to the Gregorian date Tuesday, 4 January 1774. This date lies in the tenth month of the Hijri year 1187 AH, which is Shawwal of 1187 AH. Both this Hijri and Gregorian date occur on the single day that is Tuesday without any doubt. The Arabic date 1187/10/21 is calculated using the Umm Al-Qura calendar and the sighting of the moon. One thing to remember is that this Arabic date may occur on different Gregorian date depending upon the region and country and obviously the moon.
If you are still not sure about the date then you can use our Arabic date converter.
The following is the conversion of the Gregorian date 4 January 1774 to its equivalent Arabic date.
The following is the conversion of the Arabic date 21 Shawwal 1187 AH to its equivalent Gregorian date.
فَلَنُذِيقَنَّ ٱلَّذِينَ كَفَرُوا۟ عَذَابًۭا شَدِيدًۭا وَلَنَجْزِيَنَّهُمْ أَسْوَأَ ٱلَّذِى كَانُوا۟ يَعْمَلُونَ
But verily We shall cause those who disbelieve to taste an awful doom, and verily We shall requite them the worst of what they used to do.
Surah Fussilat(41:27)