If we start with the complete alphabet:

ABCDEFGHIJKLMNOPQRSTUVWXYZ

and choose 19 of the letters to remove, for instance like this:

A---E--H-JK------R------Y-,

that will leave the alphabetically ordered 7-letter "word" AEHJKRY.

So from the 26 letters we want to choose 19 to remove.

Answer: C(26,19) = 657800

Edwin