pattern - What is a Devilish Phrase™/Word™?

_{This is in the spirit of the What is a Word/Phrase™ series started by JLee with a special brand of Phrase™ and Word™ puzzles.}

If a word conforms to a special rule, I call it a Devilish Phrase™/Word™.

Use the following examples below to find the rule.

And, if you want to analyze, here is a CSV version:

DEVILISH PHRASE™/WORD™, NOT DEVILISH PHRASE™/WORD™
LUCIFER HELL, LUCIFER KINGDOM
IMAGE OF SATAN, SATAN IS BAD
WICKED WILL, WICKED SOUL
SANTA CLAUS, DISNEY CHANNEL
HELICOPTER, CHOPPER
STUBBORN, DETERMINED
DARK MATTER, BLACK HOLE
GOD INCARNATE, HEAVEN

DEMONIC EVIL, EVIL TWIN
PICTURES, IMAGES
PAPA SMURF, MAMA SMURF
HELL BURNS, BURNING FIRE
KNIGHTHOOD, CHIVALRY
CORRUPT, IMMORAL
COMMERCIALS, ADVERTISEMENTS
TELEPORT, TELESCOPE
SANSKRIT, URDU
COMPUTER, MACHINE

Answer

A word or phrase is Devilish™, when ...

... its English Gematria equals the Number of the Beast, 666.

Gematria is a system of assigning numbers to words that is used mainly in religious texts. The English Gematria assigns to each word or phrase six times the sum of the position of each letter in the alphabet. So the Gematria of ACE would be 6 + 18 + 30 = 6×(1 + 3 + 5) = 54.

The factor of six is probably only there to make it easier to form well-known evil (666) or good (888) numbers.

It is known ...

... that there are calculators that operate on Gematria. :)