six

Dictionary of Biblical Words:

One short of perfection, and characteristic of everything in this world; 666 is the number of “the beast” in the Revelation.

Concise Bible Dictionary:

See NUMBERS AS SYMBOLS.

Strong’s Dictionary of Greek Words:

Number:
1803 (find all occurrences in KJV Bible)
Greek:
ἕξ
Transliteration:
hex
Phonic:
hex
Meaning:
a primary numeral; six
KJV Usage:
six