Well, the Hijri date 4 Rajab 1421 corresponds to the Gregorian date Sunday, 1 October 2000. This date lies in the seventh month of the Hijri year 1421 AH, which is Rajab of 1421 AH. Both this Hijri and Gregorian date occur on the single day that is Sunday without any doubt. The Arabic date 1421/07/04 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 October 2000 to its equivalent Arabic date.
The following is the conversion of the Arabic date 4 Rajab 1421 AH to its equivalent Gregorian date.
ذَٰلِكَ مِنْ أَنۢبَآءِ ٱلْغَيْبِ نُوحِيهِ إِلَيْكَ ۚ وَمَا كُنتَ لَدَيْهِمْ إِذْ يُلْقُونَ أَقْلَٰمَهُمْ أَيُّهُمْ يَكْفُلُ مَرْيَمَ وَمَا كُنتَ لَدَيْهِمْ إِذْ يَخْتَصِمُونَ
This is of the tidings of things hidden. We reveal it unto thee (Muhammad). Thou wast not present with them when they threw their pens (to know) which of them should be the guardian of Mary, nor wast thou present with them when they quarrelled (thereupon).
Surah Aal-i-Imraan(3:44)