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 ← 71 72 73 →
Cardinalseventy-two
Ordinal72nd
(seventy-second)
Factorization23 × 32
Divisors1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72
Greek numeralΟΒ´
Roman numeralLXXII
Binary10010002
Ternary22003
Octal1108
Duodecimal6012

72 (seventy-two) is the natural number following 71 and preceding 73. It is half a gross or 6 dozen (i.e., 60 in duodecimal).

## In mathematics

Seventy-two is

• a pronic number, the product of 8 and 9
• 72 is the smallest Achilles number, as a powerful number that is not itself a power
• The sum of Euler's totient function φ(x) over the first fifteen integers
• a highly totient number as there are 17 solutions to the equation φ(x) = 72, more than any integer below 72.
• the smallest number whose fifth power is the sum of five smaller fifth powers: 195 + 435 + 465 + 475 + 675 = 725
• The sum of four consecutive primes (13 + 17 + 19 + 23), as well as the sum of six consecutive primes (5 + 7 + 11 + 13 + 17 + 19).
• In maths and economics, 72 plays a role in the Rule of 72.

## In religion

• The number of languages spoken at the Tower of Babylon, according to later tradition.
• The conventional number of scholars translating the Septuagint, according to the legendary account in the "Letter of Aristeas".
• The conventional number of disciples sent forth by Jesus in Luke 10 in some manuscripts (seventy in others).
• The number of names of God, according to Kabbalah (see names of God in Judaism).
• The Shemhamphorasch related to the number of the names of God.
• The total number of books in the Bible in the Catholic version if the Book of Lamentations is considered part of the Book of Jeremiah.
• The current distribution of the Book of Revelation is 22 chapters, adopted since the 13th century, but the oldest known division of the text is that of the Greek commentator Andrew of Cesary (6th century) in 72 chapters.
• The number of people martyred along with Imam Hussain at the Battle of Karbala.
• The number of houri each Muslim martyr (or every Muslim male, according to some ahadith) shall receive as companions in Paradise.
• The degrees of the Jacob's Ladder were to the number of 72, according to the Zohar.
• The 72 disciples of Confucius who mastered his teachings (also given as 77).
• Mahavira, the twenty-fourth and last tirthankara of Jainism, is said to have attained nirvana after his physical death at the age of 72.
• Thoth, in an Egyptian creation myth, wins a 72nd of each day of the year from the Moon in a game of draughts, as a favour to Nut, the Sky Goddess. He uses these portions to make the five intercalary days on which the remaining Gods and Goddesses are born.[1]
• The good god Osiris was enclosed in a coffin by 72 evil disciples and accomplices of Set.[2]
• At the age of the puberty, the young Parsee received the investiture of the sacred cord Kucti made of 72 linens in symbol of the community.
• In Cao Đài, the number of planets between hell and heaven.
• There are 72 stupas which comprise Borobudur, the world's largest Buddhist temple.
• 72 major temples have been found at Angkor, seat of the ancient Khmer Empire.
• In Islam, 72 is the number of sects or denominations that are doomed to Hell, according to Hadith (Sayings of prophet Muhammad).[3][4]
• The number of demons sealed away by King Solomon with The Lesser Key of Solomon.