# 70 (number)

 ← 69 70 71 →
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
Vigesimal 3A20
Base 36 1Y36
Hebrew

<span ="font-size:150%;">ע (

stiالعاب)
 Look up seventy in Wiktionary, the free dictionary.

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

## In mathematics

70 is:

The sum of the first 24 squares starting from 1 is 702. This relates 70 to the Leech lattice and thus string theory.

## Number name

Main article: number name

Several languages, especially ones with vigesimal number systems, do not have a specific word for 70: for example, French soixante-dix "sixty-ten"; Danish halvfjerds, short for halvfjerdsindstyve "three and a half score". (For French, this is true only in France; other French-speaking regions such as Belgium, Switzerland, Aosta Valley and Jersey use septante.[10])

## Notes

1. "Sloane's A007304 : Sphenic numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
2. 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.
3. "Sloane's A000326 : Pentagonal numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
4. "Sloane's A051865 : 13-gonal (or tridecagonal) numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
5. "Sloane's A000332 : Binomial coefficient binomial(n,4) = n*(n-1)*(n-2)*(n-3)/24". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
6. "Sloane's A006037 : Weird numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
7. "Sloane's A059756 : Erdős-Woods numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-29.
8. 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 70 mph, for normally-laden cars and motorcycles on dual-carriageways and motorways.
9. Guxi in Baidu Encyclopedia (Chinese: 七十岁，古来稀)
10. 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".
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