I'm going to take a bit of a different take on this question.
We start with #(w^3x^4y^6)^2# and distribute the square:
#w^(3xx2)x^(4xx2)y^(6xx2)=w^6x^8y^12#
This means there are a total of 6 #w# terms, 8 #x# terms, and 12 #y# terms all multiplying each other. Since we multiplication in this sense has the commutative power (in that #ab=ba#) and so the letters can be written in any order, I can write:
or any other order, just so long as I list all the variables together as being multiplied (I'm ignoring ordering via brackets)
And so there are 26 variables in total with a group of 6, a group of 8, and a group of 12. This means we can take #26!# as the numerator of a fraction which will express the ways 26 terms can be arranged, and then divide by #6!8!12!# to eliminate counting of duplicate ordering:
#(26!)/(6!8!12!)=>#
#(26xx25xxcancelcolor(blue)(24)xx23xxcancelcolor(violet)22^11xxcancelcolor(orange)(21)xxcancelcolor(pink)(20)xx19xxcancelcolor(purple)(18)^3xx17xxcancelcolor(brown)(16)xxcancelcolor(green)(15)xx14xx13xxcancelcolor(red)(12!))/(cancelcolor(blue)(6)xxcancelcolor(green)(5)xxcancelcolor(blue)(4)xxcancelcolor(green)(3)xxcancelcolor(brown)(2xx8)xxcancelcolor(orange)(7)xxcancelcolor(purple)(6)xxcancelcolor(pink)(5xx4)xxcancelcolor(orange)(3)xxcancelcolor(violet)(2)xxcancelcolor(red)(12!))=>#
#26xx25xx23xx11xx19xx3xx17xx14xx13=>#
#29,002,073,100#