Well, the Hijri date 21 Muharram 1247 corresponds to the Gregorian date Friday, 1 July 1831. This date lies in the first month of the Hijri year 1247 AH, which is Muharram of 1247 AH. Both this Hijri and Gregorian date occur on the single day that is Friday without any doubt. The Arabic date 1247/01/21 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 1 July 1831 to its equivalent Arabic date.
The following is the conversion of the Arabic date 21 Muharram 1247 AH to its equivalent Gregorian date.
فَٱنطَلَقَا حَتَّىٰٓ إِذَا رَكِبَا فِى ٱلسَّفِينَةِ خَرَقَهَا ۖ قَالَ أَخَرَقْتَهَا لِتُغْرِقَ أَهْلَهَا لَقَدْ جِئْتَ شَيْـًٔا إِمْرًۭا
So they twain set out till, when they were in the ship, he made a hole therein. (Moses) said: Hast thou made a hole therein to drown the folk thereof? Thou verily hast done a dreadful thing.
Surah Al-Kahf(18:71)