Allah's Most Beautiful Names are Tawqifiy (bound by a religious text and not amenable to personal opinion), and Allah (Exalted be He) should not be given a name unless it is mentioned in the Qur'an or the Sunnah (whatever is reported from the Prophet). Accordingly, Hannan is not one of the Names of Allah (Exalted be He). In fact, it is a description of one of His Actions. It means the One Who shows mercy and it is derived from mercy. Allah (Exalted be He) says:
And (made him) sympathetic to men as a mercy (or a grant) from Us
The Ayah (Qur'anic verse) means a mercy from Allah (Exalted be He) according to one of its two interpretations.The Hadith that indicate that Allah (Exalted be He) has the Name Al-Hannan are not authentically reported. Al-Mannan, on the other hand, is one of the Most Beautiful Names of Allah that are authentically reported. In Sunan (Hadith compilations classified by jurisprudential themes) of
Abu Dawud and
Al-Nasa'y, it was related on the authority of
Anas (may Allah be pleased with him) that the Prophet (peace be upon him) heard someone supplicating to Allah saying:
O Allah! I ask You that (Part No. 24; Page No. 173) all praise is Yours. There is no true god except You, You are Al-Mannan, the Originator of the Heavens and Earth, Possessor of Majesty and Honor. O the Ever-Living, O Self-Subsisting. The Prophet (peace be upon him) then said: He has supplicated to Allah using His Greatest Name; when supplicated with this Name, He answers, and when asked with this Name He gives.
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.