How many different words can be made using the letters of the word ' HALLUCINATION ' if all constants are together?

 H   L   C   N    T    A   U   I   O

      L        N          A        I

There are total 131 letters out of which 7 are consonants and 6 are vowels. Also ther are 2L's , 2N's, 2A's and 2I's.

If all the consonants  are together then the numberof arrangements =  $\frac{7!}{2!}$x 1/2! .

But the 7 consonants  can be arranged themselves in   $\frac{7!}{2!}$ x 1/2! ways. 

Hence the required number of ways =  $\frac{7}{!}2$ = 1587600