How can we convert a 4-byte number into hexadecimal notation?

How can we convert a 4-byte number into hexadecimal notation? I only know the dechex function, but the transfer is

Echo dechex (1407401322869 );

Afa7e975

The result of the four-byte calculator is 147afa8260.

How can I implement it using PHP?

Reply to discussion (solution)

What is your calculator?
It should be 147AFA7E975

Echo base_convert (1407401322869, 10, 16); // 147afa7e975

You have a problem with the calculator.

No, moderator. I didn't test it.
Test

Echo base_convert (1407401322869, 10, 16); // displayed as cccdc8f1ea8?

Thank you for your help.

I wrote an error in the question. The result is 147afa7e975.
But when I use base_convert, the result is cccdc8f1ea8. why?