Well, the Hijri date 21 Dhul Qidah 1321 corresponds to the Gregorian date Sunday, 7 February 1904. This date lies in the eleventh month of the Hijri year 1321 AH, which is Dhu Al-Qidah of 1321 AH. Both this Hijri and Gregorian date occur on the single day that is Sunday without any doubt. The Arabic date 1321/11/21 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 7 February 1904 to its equivalent Arabic date.
The following is the conversion of the Arabic date 21 Dhul Qidah 1321 AH to its equivalent Gregorian date.
فَقَرَأَهُۥ عَلَيْهِم مَّا كَانُوا۟ بِهِۦ مُؤْمِنِينَ
And he had read it unto them, they would not have believed in it.
Surah Ash-Shu'araa(26:199)