We do not know and do not find any evidence from Quran or hadith about numerology. We do not have any hadith even fake hadith which supports the numerology. When there is no single evidence from islam about this conversion, how can Quran then be converted into numbers?
Some people argue that numerology and nqash makes it easy for everyone to carry those big surahs of Quran that otherwise cannot be carried everywhere. Logical brains should come up with this question that, how can those numbers be same like the surah? What is the need of carrying surahs of Quran? Is there exemption from ALLAH swt that we should not understand Quran but carry it in numbers?
What is the method with which verses and surahs are converted into those numbers? Some say it is the number of words and alphabets, we say okei, the nmber represent words, what is so sacred about the number of words in a surah? Or number of alphabets in the surah? The sacred thing is surah itself not the number of its words.
Same thing we see in 786. Instead of writing complete verse people write 786 in their letters, in their speeches and on the face of their houses etc. this number 786 cannopt replace the verse which is so blessed and pure in meaning that when it was revealed, shaitan was beaten with thrones and every time when some muslim reads it satan is beaten.
This numerology has come from shiaism and today some brelvi and sufi people practice it and promote it. We must fear ALLAH and must not dare to change what HE had given us from understanding. The best way to carry Quran always is to memories it. in this way Quran wil be safe in heart and mind and there will be no need os taweez etc.