Oddly enough in a Catholic rebuttal to this fact they attempt to ( http://www.newadvent.org/library/almanac_thisrock92.htm ) diffuse the the impact by including the founder of the Seventh Day Adventism and state:
Let's consider this accusation. Latin, Greek, and Hebrew have numerical values assigned to various letters in their alphabets. In Latin the values are: I=1, V=5, X=10, L=50, C=100, D=500, M=1,000. By extension W=10 (because W=VV, or two Vs together), and U=V (because there was no letter U for the Romans; where you see the letter U in modern writing, use the letter V instead).
As you can work out for yourself, Vicarius Filii Dei does add up to 666 in Latin: Vicarius=112; Filii=53, Dei=501. (Ignore letters which are not assigned a numerical value.) The problem is that Vicarius Filii Dei is not a title of the pope. One of his titles, in fact his chief title, is Vicarius Christi (Vicar of Christ), but, unfortunately for Seventh-Day Adventists and other anti-Catholics who attempt to use this ploy, Vicarius Christi adds up to only a measly 214, not the infernal 666.
Since the average person, Catholic or Protestant, hasn't the foggiest idea what the pope's titles are in Latin or English, anti-Catholics (some of whom know better) can get away with this subterfuge.
But what if one of the pope's titles did add up to 666? Would that coincidence prove the pope is the beast? Hardly. It would prove nothing because lots of names and titles add up to 666. By using a nifty little technique you can force a Seventh-Day Adventist to admit that the addition to 666 proves nothing, even when it's a papal title that's in question. Here's how.
Have your son-in-law do the math, and he'll be shocked to learn that the name of the woman who started Seventh-Day Adventism, Ellen Gould White, adds up to 666: Ellen=100, Gould=555, White=11. Ask him whether this "proves" that the foundress of his religion was the beast? If he says "No," then the tallying of the name means nothing. If he says "Yes," then what's he doing belonging to a church founded by the beast? Either way his argument collapses. (Isn't apologetics fun?)
What they are missing is the wonderful completeness of our FATHER in bringing forth the reality that Seventh Day Adventism is also one of the Daughters of the Whore and of the Beast as it is stated there are many AntiChrists and these are typifications as well as real illustrations of the apostasy.
AND I stood upon the sand of the sea, and saw a beast rise up out of the sea,(and we stand upon the the sand of the sea - you and I standing in our generation with all the living people of the world) and saw a beast rise up out of the sea, having seven heads and ten horns, and upon his heads the name of blasphemy. ( and we see this as the governments of the world rising up out of the sea of mankind usurping all power into one central body. The number seven resounds the perfection of the governing principality's so revealing the network of nations thus constituting the power while the number ten indicates the completeness of that power. Still to be even more precise the individuality of "his" heads or leaders yet identifies them as one beast by the name of blasphemy upon their heads..)
THE SIMPLE TRUTH IS THAT THE BEAST AS SERPENT, DRAGON, WOLF IN SHEEPS CLOTHING, OR GOVERNMENTS IS WINDING ITS WAY DOWN THE STREAM OF TIME TO THIS PRESENT DAY. A DEMONSTRABLE EVIL ATTEMPTING TO SHOW ITSELF AS GOOD.
LUKE 6:43 For a good tree bringeth not forth corrupt fruit; neither doth a corrupt tree bring forth good fruit.