Memorizing the Quran
Question :

Is there a specific number of how many times a person should complete the Quran in their life, and how many Surahs they should memorize?

Answer :

It is not obligatory to complete the recite the whole of the Holy Quran, nor is it obligatory to repeat doing so. However, it is highly recommended to do so.
Likewise, it is not obligatory to memorize any surah, so one could recite even the chapter of Al-Fatiha during prayers by reading it.

Memorizing the Quran
Question :

I want to memorize the entire Quran. Is there a supplication to help me?

Answer :

May Allah accept from you your endeavors, and consider you one of those who act upon the words of Holy Quran and amongst those who can benefit from the Quran in this life and in the hereafter. Unfortunately, we are not aware of a supplication to memorize the Holy Book specifically. However, the following supplication is reported to strengthen the memory, and it is recited after the prayers:


سبحان من لا يعتدي على أهل مملكته، سبحان من لا يأخذ أهل الأرض بألوان العذاب، سبحان الرؤوف الرحيم. اللهم إجعل لي في قلبي نوراً وبصراً وفهماً وعلماً، إنك على كل شيء قدير


Translation:
Glory be to Him Who does not treat the people of His realm with transgression!
Glory be to Him Who does not inflict on the inhabitants of the earth various sorts of torture! Glory be to the Affectionate, the Merciful!
Oh Allah, place in my heart illumination, discernment, understanding, and knowledge! Verily, You have power over all things.