224 (two hundred [and] twenty-four) is the natural number following 223 and preceding 225.
| ||||
|---|---|---|---|---|
| Cardinal | two hundred twenty-four | |||
| Ordinal | 224th (two hundred twenty-fourth) | |||
| Factorization | 25 × 7 | |||
| Prime | No | |||
| Greek numeral | ΣΚΔ´ | |||
| Roman numeral | CCXXIV, ccxxiv | |||
| Binary | 111000002 | |||
| Ternary | 220223 | |||
| Senary | 10126 | |||
| Octal | 3408 | |||
| Duodecimal | 16812 | |||
| Hexadecimal | E016 | |||
224 is a practical number, [1] and a sum of two positive cubes 23 + 63. [2] It is also 23 + 33 + 43 + 53, making it one of the smallest numbers to be the sum of distinct positive cubes in more than one way. [3]
224 is the smallest k with λ(k) = 24, where λ(k) is the Carmichael function. [4]
The mathematician and philosopher Alex Bellos 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 [the English-language version of] Wikipedia". [5] That distinction now belongs to 315.
In the SHA-2 family of six cryptographic hash functions, the weakest is SHA-224, named because it produces 224-bit hash values. [6] 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. [7]
The ancient Phoenician shekel was a standardized measure of silver, equal to 224 grains, although other forms of the shekel employed in other ancient cultures (including the Babylonians and Hebrews) had different measures. [8] Likely not coincidentally, as far as ancient Burma and Thailand, silver was measured in a unit called a tikal, equal to 224 grains. [9]