Why use hex?

Question

Hey! I was looking at this code at http://www.gnu.org/software/m68hc11/examples/primes_8c-source.html

I noticed that in some situations they used hex numbers, like i

Answer 1

0xffff0000 is easy to understand that it's 16 times "1" and 16 times "0" in a 32 bit value, while 4294901760 is magic.