224 (two hundred
ndtwenty-four) is the natural number following
223
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Year 223 (Roman numerals, CCXXIII) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Maximus and Aelianus (or, less frequen ...
and preceding
225
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Year 225 ( CCXXV) was a common year starting on Saturday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Fuscus and Domitius (or, less frequently, year 978 '' ...
.
In mathematics
224 is a
practical number,
and a sum of two positive cubes . It is also , making it one of the smallest numbers to be the sum of distinct positive cubes in more than one way.
224 is the smallest ''k'' with λ(''k'') = 24, where λ(''k'') is the
Carmichael function
In number theory, a branch of mathematics, the Carmichael function of a positive integer is the smallest positive integer such that
:a^m \equiv 1 \pmod
holds for every integer coprime to . In algebraic terms, is the exponent of the multip ...
.
The mathematician and philosopher
Alex Bellos
Alexander Bellos (born 1969) is a British writer, broadcaster and mathematics communicator.Alex Bellos He is the author of books about Brazil and mathematics, as well as having a column in ''The Guardian'' newspaper.
Education and early life ...
suggested in 2014 that a candidate for the lowest
uninteresting number would be 224 because it was, at the time, "the lowest number not to have its own page on
he English-language version ofWikipedia
Wikipedia is a multilingual free online encyclopedia written and maintained by a community of volunteers, known as Wikipedians, through open collaboration and using a wiki-based editing system. Wikipedia is the largest and most-read refer ...
".
In other areas
In the
SHA-2
SHA-2 (Secure Hash Algorithm 2) is a set of cryptographic hash functions designed by the United States National Security Agency (NSA) and first published in 2001. They are built using the Merkle–Damgård construction, from a one-way compression ...
family of six
cryptographic hash function
A cryptographic hash function (CHF) is a hash algorithm (a map of an arbitrary binary string to a binary string with fixed size of n bits) that has special properties desirable for cryptography:
* the probability of a particular n-bit output re ...
s, the weakest is SHA-224, named because it produces 224-bit hash values. It was defined in this way so that the number of bits of security it provides (half of its output length, 112 bits) would match the key length of two-key
Triple DES
In cryptography, Triple DES (3DES or TDES), officially the Triple Data Encryption Algorithm (TDEA or Triple DEA), is a symmetric-key block cipher, which applies the DES cipher algorithm three times to each data block. The Data Encryption Standa ...
.
The ancient Phoenician
shekel
Shekel or sheqel ( akk, 𒅆𒅗𒇻 ''šiqlu'' or ''siqlu,'' he, שקל, plural he, שקלים or shekels, Phoenician: ) is an ancient Mesopotamian coin, usually of silver. A shekel was first a unit of weight—very roughly —and became c ...
was a standardized measure of
silver
Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical ...
, equal to 224 grains, although other forms of the shekel employed in other ancient cultures (including the Babylonians and Hebrews) had different measures. Likely not coincidentally, as far as ancient
Burma
Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...
and
Thailand
Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is b ...
, silver was measured in a unit called a ''tikal'', equal to 224 grains.
See also
*
224 (disambiguation)
References
Integers
{{Num-stub