We have 5 vowels and 21 consonants.
select : 2 vowels and 2 consonants
We can choose 2 vowels from 5 in 5C2 ways = 10 ways
We can choose 2 consonants from 21 in 21C2 ways = 210 ways
Now these selected 4 letters can be arranged in 4! ways = 24 ways
By fundamental theorem,
total number of ways(words) = 10*210*24
= 50400