It turned-out that there is more to 19 than simple counting. There exists relations between the verses which are also multiples of 19. Example, each verse in the Quran has four identifiers: chapter number, verse number, word count, letter count.
If we replace the first verse in the Quran by its four identifiers we get a unique number "11419"; this number is a multiple of 19. If we replace the entire Quran by the same method we get one very huge number, but it also turned out to be a multiple of 19. (See proof)
The first number "11419" consists of 5 digits and it would have been very easy for a human to divide by 19. However the second number is very huge and consists of 46500 digits, which means it would have been impossible for a human to know if it is a multiple of 19. The probability of this to be correct by chance is 0.0004616805.
How could an illiterate man who lived 1400 years ago have known about relational algebra?
(In the Christian Bible Jesus insists that the only sign we should verify is him being in the grave for three days and three nights (Matthew 12:38-40). So we are checking: He was crucified on Friday afternoon, the day before the Sabbath (Mark 15:42), and then he was resurrected on Sunday morning (Mark 16:9). Between Friday afternoon and Sunday morning there is 36 hours. Can anyone fit within those 36 hours three days and three nights?)
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.