- published: 31 Jul 2016
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241 is the natural number between 240 and 242. It is also a prime number.
241 is the larger of the twin primes (239, 241). Twin primes are pairs of primes separated by 2.
241 is a regular prime and a lucky prime.
Since 241 = 15 × 24 + 1, it is a Proth prime.
241 is a repdigit in base 15 (111).
241 is the only known Lucas–Wieferich prime to (U, V) = (3, −1).
Year 241 (CCXLI) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Gordianus and Pompeianus (or, less frequently, year 994 Ab urbe condita). The denomination 241 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
A number is a mathematical object used to count, measure, and label. The original examples are the natural numbers 1, 2, 3, and so forth. A notational symbol that represents a number is called a numeral. In addition to their use in counting and measuring, numerals are often used for labels (as with telephone numbers), for ordering (as with serial numbers), and for codes (as with ISBNs). In common usage, the term number may refer to a symbol, a word, or a mathematical abstraction.
In mathematics, the notion of number has been extended over the centuries to include 0, negative numbers, rational numbers such as and , real numbers such as and , complex numbers, which extend the real numbers by including , and sometimes additional objects. Calculations with numbers are done with arithmetical operations, the most familiar being addition, subtraction, multiplication, division, and exponentiation. Their study or usage is called arithmetic. The same term may also refer to number theory, the study of the properties of the natural numbers.