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213 (number)
213 (two hundred ndthirteen) is the number following 212 and preceding 214. In mathematics 213 and the other permutations of its digits are the only three-digit number whose digit sums and digit products are equal. It is a member of the quickly-growing Levine sequence, constructed from a triangle of numbers in which each row counts the copies of each value in the row below it. As the product of the two distinct prime numbers 3 and 71, it is a semiprime, the first of a triple of three consecutive semiprimes 213, 214, and 215. Its square, 2132 = 45369, is one of only 15 known squares that can be represented as a sum of distinct factorials In mathematics, the factorial of a non-negative denoted is the product of all positive integers less than or equal The factorial also equals the product of n with the next smaller factorial: \begin n! &= n \times (n-1) \times (n-2) \t .... See also * 213 (other) References Integers {{Num-stub ca:Nombre 210#Nombres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
212 (number)
212 (two hundred ndtwelve) is the natural number following 211 and preceding 213. In mathematics * 212=2^\times53 * totient sum for the first 26 integers In other fields * +212 is the code for international direct-dial phone calls to Morocco * Area code 212, the first telephone area code used for Manhattan * "212" (song), a 2011 song by Harlem rapper Azealia Banks * 212 Medea, a very large Main belt asteroid * Bell 212 helicopter * Type 212 submarine * 212, a fragrance by Carolina Herrera * 212 action, a mass protest led by Indonesian Islamist groups * Unit 212, an Israeli commando unit also known as Maglan * In Fahrenheit degrees, the boiling point of water at sea level Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardise ... References Integers {{number-stub ca:Nomb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
214 (number)
214 (two hundred ndfourteen) is the natural number following 213 and preceding 215. In mathematics *214 is a composite number (with prime factorization 2 * 107) and a triacontakaiheptagonal number (37-gonal number). * 214!! − 1 is a 205-digit prime number. *The 11th perfect number 2106×(2107−1) has 214 divisors.Number of regions into which a figure made up of a row of 5 adjacent congruent rectangles is divided upon drawing diagonals of all possible rectangles In other fields * ''214'' is a song by Rivermaya. * 214 Aschera is a Main belt asteroid. *E214 is the E number of Ethylparaben. *The Bell 214 is a helicopter. *The Tupolev 214 is an airliner. *Type 214 submarine *There are several highways numbered 214. *Form DD 214 documents discharge from the U.S. Armed Forces. *The number of Wainwright-listed summits of the English Lake District 214 is also: *The first area code of metropolitan Dallas, Texas *The number of Chinese radicals for the writing of Chinese characters ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digit Sum
In mathematics, the digit sum of a natural number in a given number base is the sum of all its digits. For example, the digit sum of the decimal number 9045 would be 9 + 0 + 4 + 5 = 18. Definition Let n be a natural number. We define the digit sum for base b > 1 F_ : \mathbb \rightarrow \mathbb to be the following: :F_(n) = \sum_^ d_i where k = \lfloor \log_ \rfloor is the number of digits in the number in base b, and :d_i = \frac is the value of each digit of the number. For example, in base 10, the digit sum of 84001 is F_(84001) = 8 + 4 + 0 + 0 + 1 = 13. For any two bases 2 \leq b_1 < b_2 and for sufficiently large natural numbers , :.. The sum of the digits of the integers 0, 1, 2, ... is given by in the |
Semiprime
In mathematics, a semiprime is a natural number that is the product of exactly two prime numbers. The two primes in the product may equal each other, so the semiprimes include the squares of prime numbers. Because there are infinitely many prime numbers, there are also infinitely many semiprimes. Semiprimes are also called biprimes. Examples and variations The semiprimes less than 100 are: Semiprimes that are not square numbers are called discrete, distinct, or squarefree semiprimes: The semiprimes are the case k=2 of the k-almost primes, numbers with exactly k prime factors. However some sources use "semiprime" to refer to a larger set of numbers, the numbers with at most two prime factors (including unit (1), primes, and semiprimes). These are: Formula for number of semiprimes A semiprime counting formula was discovered by E. Noel and G. Panos in 2005. Let \pi_2(n) denote the number of semiprimes less than or equal to n. Then \pi_2(n) = \sum_^ pi(n/p_k) - k + 1 /math> where ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Factorials
In mathematics, the factorial of a non-negative denoted is the product of all positive integers less than or equal The factorial also equals the product of n with the next smaller factorial: \begin n! &= n \times (n-1) \times (n-2) \times (n-3) \times \cdots \times 3 \times 2 \times 1 \\ &= n\times(n-1)!\\ \end For example, 5! = 5\times 4! = 5 \times 4 \times 3 \times 2 \times 1 = 120. The value of 0! is 1, according to the convention for an empty product. Factorials have been discovered in several ancient cultures, notably in Indian mathematics in the canonical works of Jain literature, and by Jewish mystics in the Talmudic book ''Sefer Yetzirah''. The factorial operation is encountered in many areas of mathematics, notably in combinatorics, where its most basic use counts the possible distinct sequences – the permutations – of n distinct objects: there In mathematical analysis, factorials are used in power series for the exponential function and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
213 (other)
213 is a year of the Julian calendar. 213 may also refer to: * 213 (number), a natural number * 213 BC, a year of the pre-Julian Roman calendar * 213 Lilaea, a Main belt asteroid * 213 series, a type of train used by Japan National Railways * Area code 213, a telephone area code for downtown Los Angeles and environs * '' Two:Thirteen'', a 2009 suspense thriller film * 213, the apartment number of American serial killer Jeffrey Dahmer Music * 213 (group), a hip hop group consisting of Snoop Dogg, Warren G & Nate Dogg * "213", a song by Slayer from '' Divine Intervention'' * "213 (Maritime.epsosis)", a song by Squarepusher from '' Conumber E:P'' Military units * 213 Coastal Division, an Infantry Division of the Italian Army during World War II * 213th Battalion (American Legion), CEF, a unit in the Canadian Expeditionary Force during World War I * 213th Area Support Group (United States), a unit of the Pennsylvania Army National Guard See also * 2.13.61 2.13.61, Inc. is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integers
An integer is the number zero (), a positive natural number (, , , etc.) or a negative integer with a minus sign (−1, −2, −3, etc.). The negative numbers are the additive inverses of the corresponding positive numbers. In the language of mathematics, the set of integers is often denoted by the boldface or blackboard bold \mathbb. The set of natural numbers \mathbb is a subset of \mathbb, which in turn is a subset of the set of all rational numbers \mathbb, itself a subset of the real numbers \mathbb. Like the natural numbers, \mathbb is Countable set, countably infinite. An integer may be regarded as a real number that can be written without a fraction, fractional component. For example, 21, 4, 0, and −2048 are integers, while 9.75, , and are not. The integers form the smallest Group (mathematics), group and the smallest ring (mathematics), ring containing the natural numbers. In algebraic number theory, the integers are sometimes qualified as rational integers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
