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Cardinal | seventy-seven | |||

Ordinal | 77th (seventy-seventh) | |||

Factorization | 7 × 11 | |||

Divisors | 1, 7, 11, 77 | |||

Greek numeral | ΟΖ´ | |||

Roman numeral | LXXVII | |||

Binary | 1001101_{2} | |||

Ternary | 2212_{3} | |||

Quaternary | 1031_{4} | |||

Quinary | 302_{5} | |||

Senary | 205_{6} | |||

Octal | 115_{8} | |||

Duodecimal | 65_{12} | |||

Hexadecimal | 4D_{16} | |||

Vigesimal | 3H_{20} | |||

Base 36 | 25_{36} |

**77** (**seventy-seven**) is the natural number following 76 and preceding 78. Seventy-seven is the smallest positive integer requiring five syllables in English.

## Contents

## In mathematics

**77** is:

- the 22nd discrete biprime and the first of the (7.q) family.
- a Blum integer since both 7 and 11 are Gaussian primes.
^{[1]} - the sum of three consecutive squares, 4
^{2}+ 5^{2}+ 6^{2}. - the sum of the first eight prime numbers.
- the number of integer partitions of the number 12.
^{[2]} - the largest number that cannot be written as a sum of distinct numbers whose reciprocals sum to 1.
^{[3]} - the number of digits of the 12th perfect number.
^{[4]}

It is possible for a sudoku puzzle to have as many as 77 givens, yet lack a unique solution.^{[5]}

It and its *sibling* 49 are the only 2-digit numbers whose home primes (in base 10) have not been calculated.

## In science

- The atomic number of iridium
- The boiling point of nitrogen

## In history

During World War II in Sweden at the border with Norway, "77" was used as a shibboleth (password), because the tricky pronunciation in Swedish made it easy to instantly discern whether the speaker was native Swedish, Norwegian, or German.^{[6]}

## In religion

In the Islamic tradition, "77" figures prominently. Muhammad is reported to have explained, "Faith has sixty-odd, or seventy-odd branches, the highest and best of which is to declare that there is no god but God, and the lowest of which is to remove something harmful from a road. Shyness, too, is a branch of faith." While some scholars refrain from clarifying "sixty-odd or seventy-odd", various numbers have been suggested, 77 being the most common.^{[7]} Some have gone so far as to delineate these branches.^{[8]}

The Gospel of Luke lists 77 generations from Adam to Jesus.^{[9]}

### In religious numerology

In certain numerological systems based on the English alphabet, the number 77 is associated with Jesus Christ. CHRIST is C = 3, H = 8, R = 18, I = 9, S = 19, T = 20, which added together equal 77.

'Liber 77' is the gematrian name for Liber OZ- a brief but popular publication by Aliester Crowley. The word 'oz', which means 'strength', is composed of two hebrew letters- ayin and zayin, which have gematrian values of 70 and 7 respectively, thus adding up to 77.

## In other fields

**Seventy-seven** is also:

- 10-77 – the New York City Fire Department's (FDNY) 10 code for high-rise, multiple-dwelling fire
^{[10]} - Shortening of a 1950s-60s TV series,
*77 Sunset Strip* - Group of 77, a group of developing nations at the United Nations
- 77 – Talking Heads's debut album (
*Talking Heads: 77*) released in 1977 - The 77's, an American Rock band
- The temperature, in Fahrenheit, some characteristics of semiconductors are specifically given in a datasheet (77 °F = 25 °C).

## References

**^**Sloane, N. J. A. (ed.). "Sequence A016105 (Blum integers)".*The On-Line Encyclopedia of Integer Sequences*. OEIS Foundation. Retrieved 2016-05-29.**^**Sloane, N. J. A. (ed.). "Sequence A000041".*The On-Line Encyclopedia of Integer Sequences*. OEIS Foundation.**^**"What's Special About This Number?".**^**Caldwell, Chris K. "Mersenne Primes: History, Theorems and Lists".**^**The Science behind Sudoku, J.P. Delahaye**^**Buchan, Jamie (2010),*Easy as Pi: The Countless Ways We Use Numbers Every Day*, Penguin, ISBN 9781606522783.**^**"A Verdict of Mufti Muhammad Hassan". Archived from the original on 2008-12-04. Retrieved 2008-05-29.**^**"Imam al-Tahanawi on the Seventy-Seven Branches". Archived from the original on 2009-06-20. Retrieved 2008-05-29.**^**"The genealogy of Jesus".**^**"10 Codes".

## External links

Media related to 77 (number) at Wikimedia Commons