Reference: Kitaab al-Hadaa.iq libnil-Jowzee v1 p24, Tathkiratul-Huffaath v1 p380
said:
'Abdur-Rahmaan ibn Mahdee dictated 20,000 hadeeth to us from memory.

Reference: Kitaab al-Hadaa.iq libnil-Jowzee v1 p24, Tathkiratul-Huffaath v1 p380
'Ubaydullaah ibn 'Umar al-Qawaareeree رحمه الله said:
'Abdur-Rahmaan ibn Mahdee dictated 20,000 hadeeth to us from memory.
Graduate of the Islaamic University of Madeenah, having completed the Arabic Language programme at the Institute of Arabic Language before progressing to the Faculty of Sharee'ah, from which he graduated in 2004.