The President said the royal father, who he said upheld the culture and traditions of his people during his reign, would be remembered.
Buhari, in a statement issued by his Special Adviser on Media and Publicity, Mr Femi Adesina in Abuja on Sunday, said he shared the grief of the people of the Katagum Emirate.
According to him, he also shares condolences with all who mourn the death of the royal father.
He said the deceased was a symbol of peace, who dedicated himself to the cause of fostering unity around the country.
The President noted that Umar was a former Minister of Internal Affairs and legislator in the Northern House of Assembly in the First Republic and later, the Emir of Katagum.
Buhari said deceased served the country diligently with honour and distinction.
The President said the royal father, who he said upheld the culture and traditions of his people during his reign, would be remembered and honoured for his humility.
He also said that Umar would also be remembered for his dignity and profound contributions to national development.
Buhari urged all who mourned the monarch to reflect on his worthy services of over three decades to his people and the nation.
He said they could do this by honouring the deceased’s legacy of strengthening the peaceful co-existence of Nigerians from different tribes and traditions.
The President prayed Almighty Allah to comfort all who mourned him and bring forth a worthy successor to take his place on the revered throne of Katagum.
The late emir, who died at the age of 89 on Saturday after a protracted illness, left behind 49 children among who is Mustapha Katagum, the Yariman Katagum.