Yahya bin Bukayr said: Umar (may Allah be pleased with him) was made caliph in Rajab of the year 13 AH, and he was martyred at the end of Dhu al-Hijjah in the year 23 AH. He lived for three days after being stabbed, then died at the end of Dhu al-Hijjah. Suhayb (may Allah be pleased with him) led his funeral prayer, his son Abdullah bin Umar washed him, he was shrouded in five garments, and he was buried beside the Messenger of Allah (peace and blessings be upon him). He was stabbed on a Wednesday, with nine nights remaining of Dhu al-Hijjah. Some people say that he died that same day. As for his age at the time of his death, as I heard Malik bin Anas mention, he had reached the age of the Messenger of Allah (peace and blessings be upon him), that is, sixty-three. Some people say: fifty-nine; some say: fifty-three or fifty-five; and some say: fifty-four. His caliphate lasted ten years, four months and some days.
Hadith Referenceالمعجم الكبير للطبراني / العشرة / 72