70 (number)

← 69 70 71 →
← 70 71 72 73 74 75 76 77 78 79 → List of numbers — Integers ← 0 10 20 30 40 50 60 70 80 90 →
Cardinal	seventy
Ordinal	70th (seventieth)
Factorization	2 × 5 × 7
Divisors	1, 2, 5, 7, 10, 14, 35, 70
Roman numeral	LXX
Binary	10001102
Ternary	21213
Quaternary	10124
Quinary	2405
Senary	1546
Octal	1068
Duodecimal	5A12
Hexadecimal	4616
Vigesimal	3A20
Base 36	1Y36
Hebrew	ע (Ayin)

70 (seventy) is the natural number following 69 and preceding 71.

In mathematics

70 is:

• a sphenic number because it factors as 3 distinct primes.
• a Pell number and a generalized heptagonal number, one of only two numbers to be both.^[1]
• the seventh pentagonal number.
• the fourth triskaidecagonal number.
• the fifth pentatope number.
• the smallest Weird Number; a natural number that is abundant but not Semiperfect.
• a palindromic number in bases 9 (77₉), 13 (55₁₃) and 34 (22₃₄).
• a Harshad number in bases 6, 8, 9, 10, 11, 13, 14, 15 and 16.
• an Erdős–Woods number, since it is possible to find sequences of 70 consecutive integers such that each inner member shares a factor with either the first or the last member.

The sum of the first twenty four squares starting from one is seventy squared. This relates seventy to the Leech lattice and thus string theory.

In science

• 70 is the atomic number of ytterbium, a lanthanide

Astronomy

• Messier object M70, a magnitude 9.0 globular cluster in the constellation Sagittarius
• The New General Catalogue object NGC 70, a magnitude 13.4 spiral galaxy in the constellation Andromeda
• The Saros number of the solar eclipse series which began on 821 BC September 5 and ended on 676 February. The duration of Saros series 70 was 1496.5 years, and it contained 84 solar eclipses. Further, the Saros number of the lunar eclipse series which began on 519 BC June 13 and ended on 761 July. The duration of Saros series 70 was 1280.1 years, and it contained 72 lunar eclipses.

In religion

• Seventy souls went down to Egypt to begin the Hebrew's Egyptian exile (Genesis 46:27)
• According to Jewish tradition, there is a core of 70 nations and 70 world languages, paralleling the 70 names in the Table of Nations.
• In Jewish tradition, there were 70 men in the Great Sanhedrin, the Supreme Court of ancient Israel. (Sanhedrin 1:4).
• Likewise, according to the Jewish Aggada, there are 70 perspectives ("faces") to the Torah (Numbers Rabbah 13:15).
• Seventy elders were assembled by Moses on God's command in the desert (Numbers 11:16-30)
• Ptolemy II Philadelphus ordered 72 Jewish elders to translate the Torah into Greek; the result was the Septuagint (from the Latin for "seventy")
• The Roman numeral seventy, LXX, is the scholarly symbol for the Septuagint.
• In the Gospel of Matthew, 18:21-22, Jesus tells Peter to forgive people seventy times seven times.
• In the Gospel of Luke 10:1-24, Jesus appoints Seventy Disciples and sends them out in pairs to preach the Gospel.
• Seventy, a priesthood office in the Latter Day Saint religion.
• The Old Testament allots three score and ten (70 years) for a man's life (Psalm 90:10), and the Mishnah attributes that age to "strength" (Avot 5:32), as one who survives that age is described by the verse as "the strong"
• In Islamic history, 70 are the number of the dead among prophet Muhammad's adversary during the Battle of Badr
• In Islam, 70 are the number of Prophet Muhammad's followers martyred at the Battle of Uhud
• In Shia Islam, 70 are the number of martyr among Imam Hussein's followers during the tragedy of Karbala

In law

• 70 years: Expiration of copyrights

In sports

• NASCAR J. D. McDuffie was known for driving car #70
• in Olympic Archery, the targets are 70 meters from the archers
• College Football Clemson University gave up 70 points to WVU in the Orange Bowl in 2012: Setting the record as the most points ever given up in the history of all bowl games.

In other fields

70 is:

• the designation of USA Interstate 70, a freeway that goes from Utah to Maryland
• Municipal Okrug 70, name of Kolomyagi Municipal Okrug of Primorsky District of Saint Petersburg, Russia, until February 2011
• In miles per hour, a common speed limit for freeways in many American states, primarily in the central United States (in the Eastern U.S. the speed limit is generally 65, in the Western U.S. it is 75).
• In miles per hour, the national speed limit in the United Kingdom (for cars and motorcycles on the best grades of road).^[2]
• In years of marriage, the platinum wedding anniversary
• The hull number of the U.S. Navy's nuclear aircraft carrier USS Carl Vinson (CVN-70), named after U.S. Representative Carl Vinson.
• The number of the French department Haute-Saône
• Historical years: AD 70, 70 BC, or 1970.
• The number 70 is frequently referenced by the musical duo Boards of Canada: they have songs titled "Sixtyten" (Music Has the Right to Children, 1998) and "The Smallest Weird Number" (Geogaddi, 2002), and their record label is named Music70.
• In the Far Eastern culture of China, Japan, Korea, etc., 70 years old is called the Rare Age of the Olden Times (古稀 Guxi in Chinese, 古稀 Koki in Japanese, 고희 Gohui in Korean, etc.), as written in one of Du Fu’s poems.^[3]

Number name

The French do not have a word for 70, instead using "soixante-dix" (60 + 10). Other French-speaking countries such as Belgium, Switzerland, Aosta Valley and Jersey do have a word for it, using "septante."^[4]

Notes

1. Rao, B. Srinivasa (2005), "Heptagonal Numbers in the Pell Sequence and Diophantine Equations 2x² = y²(5y − 3)² ± 2", Fibonacci Quarterly 43 (3): 194–201.
2. The Official Highway Code, pub. Department for Transport (Revised 2007 Edition). ISBN 978-0-11-552814-9. A white circular sign with a black diagonal stripe indicates that the national speed limit applies. This depends on the vehicle type and grade of road. The table on p.40 shows the highest speed permitted to be 70mph, for normally-laden cars and motorcycles on dual-carriageways and motorways.
3. Guxi in Baidu Encyclopedia (Chinese: 七十岁，古来稀)
4. Peter Higgins, Number Story. London: Copernicus Books (2008): 19. "Belgian French speakers however grew tired of this and introduced the new names septante, octante, nonante etc. for these numbers".