Sahih Muslim Book 035, Hadith Number 6475.

Chapter : The names of Allah, the Exalted, and the merit of one who enumerates them.

Abu Huraira reported Allah's Messenger (may peace be upon him) as saying: There are ninety-nine names of Allah; he who commits them to memory would get into Paradise. Verily, Allah is Odd (He is one, and it is an odd number) and He loves odd number. And in the narration of Ibn 'Umar (the words are): "He who enumerated them."