Well, the Hijri date 21 Rabi Al Awwal 1613 corresponds to the Gregorian date Wednesday, 4 October 2186. This date lies in the third month of the Hijri year 1613 AH, which is Rabi Al-Awwal of 1613 AH. Both this Hijri and Gregorian date occur on the single day that is Wednesday without any doubt. The Arabic date 1613/03/21 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 October 2186 to its equivalent Arabic date.
The following is the conversion of the Arabic date 21 Rabi Al Awwal 1613 AH to its equivalent Gregorian date.
وَكَذَٰلِكَ نُفَصِّلُ ٱلْءَايَٰتِ وَلَعَلَّهُمْ يَرْجِعُونَ
Thus we detail the revelations, that haply they may return.
Surah Al-A'raaf(7:174)