As-Salaam alaikum,
Just spread your left hand palm, you will see the number 81 written in Arabic; and spread your right hand palm, you will see the number 18 written in Arabic.
Add 81 and 18, it gives you 99, the total number of Names of Allah in the Holy Qur'an. Subtract 18 from 81 gives you 63, the total years of Prophet Muhammad, Sallallahu alaihi Wasallam,
lived on this earth.

If you multiply the two digits of 99... that is 9 x 9 it will return you your left palm number of 81; and if you multiply the two digits of 63.. that is 6 x 3 it will return you your right palm number of 18.

Note that if you reverse the digits of 81 it will give you 18, and if reversing the digits of 18 gives you 81.. The common denominator of 81 and 18 is 3 and 9. Now, let us see what numbers they give after division:-

81 divide by 3 = 27 and 81 divide by 9 = 9. The Qur'an was revealed on 27th day of 9th month of the Islamic Calendar (lunar). Another mathematical mystery is if you write the digits of 81 and 18 serially: 8+ 1+1 + 8 you get 18. Now, what is so special about 18 here is that chapter 18 of the Holy Qur'an , ayat/verse 18 mentioned something about RIGHT SIDE and LEFT SIDE...