What is a factor tree of 64?

A factor tree of 64 is:

64
8 x 8
(2x4) x (2x4)
(2 x (2x2)) x (2 x (2x2))

It is finished now that you have arrived at only prime numbers.
The resulting prime factors of 64 are 2, 2, 2, 2, 2, and 2.

Another one is:
64
= 2 x 32
= 2 x 2 x 16
= 2 x 2 x 2 x 8
= 2 x 2 x 2 x 2 x 4
= 2 x 2 x 2 x 2 x 2 x 2

2 x 2 x 2 x 2 x 2 x 2 can also be written 26.