First we calculate how the arrangement will be made.
For example CCVCCV or CVVCCC, etc. 

There are 6C2 places to choose to put vowels.
That leaves 4C4 = 1 way to put consonants. 

For each of those we can choose and position 4 
consonants 21P4 ways.
For each of those we can choose and position 2 
vowels 5P2 ways.

Answer: 

(6C2)(4C4)(21P4)(5P2) = (12)(1)(143640)(20) = 34473600

Edwin