In Christian biblical tradition, the number 666 is famously identified as the 'number of the beast' in Revelation 13:18. It is associated with the Antichrist, evil, and ultimate rebellion against God. The number is often interpreted as a symbol of imperfection, falling short of the divine number seven, and serves as a warning against idolatry, materialism, and allegiance to worldly powers. Early Christian commentators, such as Irenaeus, considered 666 a coded reference to oppressive rulers and corrupt systems. Dreaming of 666 may thus symbolize spiritual danger, temptation, or a call to vigilance and faithfulness in the face of moral challenges.

In Buddhism, numbers themselves are generally neutral, but repeated patterns can symbolize attachment, illusion, or cycles of suffering (samsara). The repetition in 666 may be interpreted as being trapped in cycles of craving, aversion, and ignorance—the three poisons. Dreaming of 666 could signal the need to break free from negative patterns and cultivate mindfulness, compassion, and wisdom to transcend suffering and achieve liberation.

Culturally, especially in Western societies, 666 is widely recognized as a symbol of bad luck, evil, or the occult, largely due to its biblical roots and portrayal in media. It often evokes fear, superstition, and fascination with the forbidden. In dreams, encountering 666 may reflect societal anxieties, taboo-breaking, or a reaction to cultural narratives about good and evil. In some subcultures, it may also be embraced as a symbol of rebellion, nonconformity, or countercultural identity.

Hinduism assigns symbolic meanings to numbers, but 666 does not have a specific traditional significance. However, the repetition of sixes may be interpreted as an emphasis on the material world, as the number six is sometimes linked to the senses and sensual pleasures. Dreaming of 666 could be seen as a reminder to balance material pursuits with spiritual growth, and to avoid falling into the trap of maya (illusion) and attachment. It may also signal the need for self-discipline and spiritual focus.

In Islamic tradition, the number 666 does not carry any inherent negative or evil connotation in the Qur'an or Hadith. While some apocryphal or folk traditions may reference 666 due to its biblical associations, Islam emphasizes that numbers themselves are not intrinsically good or bad; rather, it is human actions and intentions that matter. Occasionally, 666 is mistakenly associated with the Qur'an because some claim it has 6,666 verses, but this is inaccurate. Dreaming of 666 in an Islamic context may reflect anxieties about misguidance, succumbing to non-Islamic fears, or being influenced by external cultural narratives rather than any doctrinal warning.

Psychologically, the number 666 often evokes subconscious associations with taboo, fear, and the shadow self, due to its ominous reputation in popular culture. Jungian analysis might interpret the appearance of 666 in dreams as the psyche's way of confronting repressed fears, guilt, or aspects of oneself deemed unacceptable. It can also represent anxiety about violating societal norms, fear of moral failure, or internal conflict. The dream may signal a need to acknowledge and integrate shadow aspects for personal growth and wholeness.

Spiritually, 666 is often seen as a symbol of materialism, imbalance, and the dominance of ego over spirit. Esoteric traditions interpret 666 as a warning against becoming overly attached to the material world or neglecting one's higher purpose. It may also represent the need to restore harmony between body, mind, and spirit. Encountering 666 in dreams can be a call to examine one's values, transcend lower desires, and realign with spiritual purpose and authenticity.