Answer
(Fatwa: 580/580/M=1431)
We are not aware of any proof with said specified numbers; however the Zikr of لا اله الا الله is superior to all other forms of Zikr. There are countless virtues mentioned in hadith regarding it. Hadhrat Shaikh Zakaria (رحمة الله عليه) has written in Fazail Aamal, that Shaikh Abu Yazeed Qurtabi said: I heard that a person who reads لااله الا الله seventy thousand times, he shall get rid of hellfire.” (Fazail Amal, 1/387)
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband