From Sahih Muslim (Hadith 6809):
Abu Huraira reported Allah's Messenger (ﷺ) 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
Reference: Muslim 6809