We use base-10 in everyday mathematics, however computers use base-2. It turned-out that the Quran is encoded with base-19.
Some chapters start with letters that have no meaning in Arabic:
٢ تِلْكَ آيَاتُ الْكِتَابِ الْمُبِينِ
٣ لَعَلَّكَ بَاخِعٌ نَفْسَكَ أَلَّا يَكُونُوا مُؤْمِنِينَ
٤ إِنْ نَشَأْ نُنَزِّلْ عَلَيْهِمْ مِنَ السَّمَاءِ آيَةً فَظَلَّتْ أَعْنَاقُهُمْ لَهَا خَاضِعِينَ
"Ta, Seen, Meem, these are verses of the clarifying book" this verse is referring to the three letters Ta, Seen, Meem. We know that the Quran has 6236 verses however this is in base-10. In base-19 the Quran has H54 verses.
Converting 6236 in base-10 to base-19 from www.unitconversion.org:
So the Quran has H54 verses in base-19.
When we replace those letters by their count we get the number of verses in the Quran in base-19 H54. These are the letters and how many times they appear in those verses:
And this is their count in base-19:
Ta, Seen, Meem turned out to be H54 in base-19. This is 6236 in base-10 (17x19x19 + 5x19 + 4) the exact number of verses in the Quran.
If a single verse was added or removed from anywhere in the entire Quran this code would have been broken.
How could an illiterate man who lived 1400 years ago have known about base-19?
The Quran (Koran, the book of Islam) contains scientific knowledge that could not have been known 1400 years ago. It ranges from basic arithmetics to the most advanced topics in astrophysics. You are invited to go through those miracles and judge for yourself.