It is now tallest building in the world and landmark of dubai. But, during construction stage dubai face big crisis to complete this project. The total cost is $1.5 billion dollars. That is huge.
After that dubai neighbour state Abu dhabi(capitial of UAE) came forward to help dubai by lending the money. To honour the president of the UAE and the ruler of Abu Dhabi who helped Dubai in need, the name was changed at the last moment, just few days before its opening from its original name Bur Dubai to Burj Khalifa (Burj- tower and Khalifa- Abu Dhabi’s ruler SHEIKH KHALIFA BIN ZAYED AL NAHYAN. Khalifa’s tower)..
The actual story of burj khalifa, you will find here - https://www.uaecentral.com/burj-khalifa-the-emperor-of-architecture/ (Birth Story, Financial Output)