|
Number: 21 |
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| Facts about the number: 21 is the number of points required to win a game in badminton and table tennis (before 2001). 21 is the number of trump cards of the tarot deck if one does not consider The Fool to be a proper trump card. 21 is the number of demands which were sent to the Chinese government by the Japanese government of Okuma Shigenobu in 1915. 21 is the smallest natural number that is not close to a power of 2, 2^n, where the range of closeness is +- n. 21 is the smallest number of distinct squares needed to tile a square. 21 is the fifth discrete Semiprime and the second in the (3.q) family. 21 is the smallest number of differently sized squares needed to square the square. |
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| The number of digits in the number: \( n \): \( d = \lfloor \log_{10}(n) \rfloor + 1 \) |
2 | |
| Sum of the digits: \( n \): \( S = \sum_{i=1}^{k} d_i \) |
3 | |
| Reverse number: \( \text{Reverse}(n) = \sum_{i=1}^{k} d_i \cdot 10^{k-i} \) |
0.047619047619048 | |
| Binary number system: \( n = \sum_{i=0}^{k-1} d_i \cdot 2^i \) |
100001010100 | |
| Hexadecimal number system: \( n = \sum_{i=0}^{k-1} d_i \cdot 16^i \) |
854 | |
| Parity of the number: \( \text{Parity}(n) = n \mod 2 \) |
odd | |
| Simplicity of the number: \(\text{IsPrime}(n) = n > 1 \land \forall d \in [2, \sqrt{n}], n \mod d \neq 0\) |
false | |
| The square root: \(\sqrt{n} = n^{\frac{1}{2}}\) |
4.5825756949558 | |
| The factorial of the number: \( n!=n \times (n-1) \times (n-2) \times \ldots \times 2 \times 1 \) |
5.1090942171709E+19 | |
| The sign of the number: \(\text{sign}(n) = \begin{cases} 1, & \text{if } n>0 \ 0, & \text{if } n=0 \ -1, & \text{if } n<0 \end{cases}\) |
+ | |
| The nearest multiple of 10: \(\text{10}(n) = 10 \times \left\lfloor \frac{n + 5}{10} \right\rfloor\) |
0 | |
| The nearest multiple of 100: \(\text{100}(n) = 100 \times \left\lfloor \frac{n + 50}{100} \right\rfloor\) |
0 | |
| Sine: \(\sin(x) = \sum_{n=0}^{\infty} \frac{(-1)^n x^{2n+1}}{(2n+1)!}\) |
0.83665563853606 | |
| Cosine: \(\cos(x) = \sum_{n=0}^{\infty} \frac{(-1)^n x^{2n}}{(2n)!}\) |
-0.54772926022427 | |
| Tangent: \(\tan(x) = \sum_{n=0}^{\infty} \frac{(-1)^n 2^{2n} (2^{2n} - 1) B_{2n} x^{2n-1}}{(2n)!}\) |
-1.5274985276366 | |
| The square of the number: \(\text{square}(n) = n^2\) |
441 | |
| Cubic root: \(\text{}(n) = \sqrt[3]{n}\) |
2.7589241763811 | |
| Natural logarithm: \(\ln(ab) = \ln(a) + \ln(b)\) |
3.0445224377234 | |
| Common logarithm: \(\log_{10}(ab) = \log_{10}(a) + \log_{10}(b)\) |
1.3222192947339 | |
| All divisors of a number: \( D(n) = \{ d \in \mathbb{Z}^+ : n \mod d = 0 \} \) |
1, 3, 7, 21 | |
| Base64: | MjEuMzI= | |
| SHA1: | 8ae0ce44c9a8287d8c2cdb422bd7716a7b0b3471 | |
| MD5: | e7d5c7938c7a1b580661b0752da7ce88 | |
| Converts a number to a Roman representation: | XXI | |
| Converting the number of seconds to days, hours, minutes and seconds: | days: 0, hours: 0, minutes: 0, seconds: 21. | |
| Converts a number to a date in UNIX time format: | ||
| Chinese: | 1970 月 1 星期四 | |
| Spanish: | 1970 Enero 1 Jueves | |
| English: | 1970 January 1 Thursday | |
| Hindi: | 1970 जनवरी 1 गुरुवार | |
| Arab: | 1970 يناير 1 الخميس | |
| Bengal: | 1970 জানুয়ারী 1 বৃহস্পতিবার | |
| Portuguese: | 1970 Janeiro 1 Quinta-feira | |
| Russian: | 1970 Январь 1 Четверг | |
| Japanese: | 1970 一月 1 木曜日 | |
| Lahnda: | 1970 جنوری 1 جمعرات | |
| Marathi: | 1970 जानेवारी 1 गुरुवार | |
| Telugu: | 1970 జనవరి 1 గురువారం | |
| Malay: | 1970 Januari 1 Khamis | |
| Turkish: | 1970 Ocak 1 Perşembe | |
| Korean: | 1970 1월 1 목요일 | |
| French: | 1970 Janvier 1 Jeudi | |
| German: | 1970 Januar 1 Donnerstag | |
| Vietnamese: | 1970 Tháng Một 1 Thứ năm | |
| Tamil: | 1970 ஜனவரி 1 வியாழக்கிழமை | |
| Urdu: | 1970 جنوری 1 جمعرات | |
| Javanese: | 1970 Januari 1 Kemis | |
| Italian: | 1970 Gennaio 1 Giovedì | |
| Persian: | 1970 ژانویه 1 پنجشنبه | |
| Gujaratis: | 1970 જાન્યુઆરી 1 ગુરુવાર | |
| Length: | ||
| 21 kilometers = 21,000.00 meters | ||
| 21 miles = 33,796.14 meters | ||
| 21 feet = 6.40 meters | ||
| 21 inches = 0.53 meters | ||
| 21 yards = 19.20 meters | ||
| 21 meters = 0.02 kilometers | ||
| 21 meters = 0.01 miles | ||
| 21 meters = 68.90 feet | ||
| 21 meters = 826.77 inches | ||
| 21 meters = 22.97 yards | ||
| Weight: | ||
| 21 pounds = 9.53 kilograms | ||
| 21 grams = 0.02 kilograms | ||
| 21 ounces = 0.60 kilograms | ||
| 21 tons = 19,050.89 kilograms | ||
| 21 kilograms = 46.30 pounds | ||
| 21 kilograms = 21,000.00 grams | ||
| 21 kilograms = 740.75 ounces | ||
| 21 kilograms = 0.02 tons | ||
| Volume: | ||
| 21 gallons = 79.49 liters | ||
| 21 milliliters = 0.02 liters | ||
| 21 cubic meters = 21,000.00 liters | ||
| 21 liters = 5.55 gallons | ||
| 21 liters = 21,000.00 milliliters | ||
| 21 liters = 0.02 cubic meters | ||
| Area: | ||
| 21 acres = 84,984.06 square meters | ||
| 21 hectares = 210,000.00 square meters | ||
| 21 square feet = 1.95 square meters | ||
| 21 square inches = 0.01 square meters | ||
| 21 square meters = 0.01 acres | ||
| 21 square meters = 0.00 hectares | ||
| 21 square meters = 226.04 square feet | ||
| 21 square meters = 32,550.07 square inches | ||
| Temperature: | ||
| 21 celsius = 69.80 fahrenheit | ||
| 21 celsius = 294.15 kelvin | ||
| 21 fahrenheit = -6.11 celsius | ||
| 21 fahrenheit = 267.04 kelvin | ||
| 21 kelvin = -252.15 celsius | ||
| 21 kelvin = -421.87 fahrenheit | ||
| Time: | ||
| 21 seconds = 0.35 minutes | ||
| 21 seconds = 0.01 hours | ||
| 21 seconds = 0.00 days | ||
| 21 minutes = 1,260.00 seconds | ||
| 21 minutes = 0.35 hours | ||
| 21 minutes = 0.01 days | ||
| 21 hours = 75,600.00 seconds | ||
| 21 hours = 1,260.00 minutes | ||
| 21 hours = 0.88 days | ||
| 21 days = 1,814,400.00 seconds | ||
| 21 days = 30,240.00 minutes | ||
| 21 days = 504.00 hours | ||
| Energy: | ||
| 21 joules = 5.02 calories | ||
| 21 joules = 0.02 kilojoules | ||
| 21 joules = 0.01 watt hours | ||
| 21 calories = 87.86 joules | ||
| 21 calories = 0.09 kilojoules | ||
| 21 kilojoules = 21,000.00 joules | ||
| 21 kilojoules = 5,019.13 calories | ||
| 21 watt hours = 75,600.00 joules | ||
| 21 watt hours = 75.60 kilojoules | ||
| Information: | ||
| 21 bytes = 0.02 kilobytes | ||
| 21 kilobytes = 21,504.00 bytes | ||
| 21 kilobytes = 0.02 megabytes | ||
| 21 megabytes = 21,504.00 kilobytes | ||
| 21 megabytes = 0.02 gigabytes | ||
| 21 gigabytes = 21,504.00 megabytes | ||
| 21 gigabytes = 0.02 terabytes | ||
| 21 terabytes = 21,504.00 gigabytes | ||