101 (number)
Category:Integers\n
101 is the
natural number following
100 and preceding
102.
In mathematics
\n101 is the 26th prime number and a
palindromic number (therefore also a
palindromic prime). The next prime is
103, with which it comprises a
twin prime. Because the period length of its reciprocal is unique among primes, 101 is a
unique prime.
101 is the sum of five consecutive primes (
13 +
17 +
19 +
23 +
29). Given 101, the
Mertens function returns
0.
For a 3-digit number in base 10, this number has a relatively simple
divisibility test. The number is split into groups of four, starting with the rightmost four, and added up to produce a 4-digit number. If this 4-digit number is of the form 1000
a + 100
b + 10
a +
b (where
a and
b are integers from 0 to 9), such as 3232 or 9797, or of the form 100
b +
b, such as 707 and 808, then the number is divisible by 101. This might not be as simple as the divisibility tests for numbers like 3 and 5, and it might not be terribly practical, but it is simpler than the divisibility tests for other 3-digit numbers.
In other fields
\n101 is also:
- The atomic number of mendelevium, an actinide.\n* The designation of US Highway 101, which runs from California to Washington.\n* In universities, sometimes the course number of basic or entry-level courses. Also used in titles of books to indicate the book is meant for a beginner. At universities with four-digit course numbers, the equivalent course number is 1001 or 1010.\n* In the title of the book The Hundred and One Dalmatians by Dodie Smith (and the various movie versions thereof).\n* The number of keys on a standard PC alphanumeric keyboard, including 12 or so function keys, cursor keys, and a numeric keypads and various other additions to the QWERTY typewriter keyboard.\n* According to Books in Print, more books are now published with a title that begins with '101' than '100'. They usually describe or discuss a list of items, such as 101 ways to ... or 101 questions and answers about .... This marketing tool is used to imply that the customer is given a little extra information beyond books that include only 100 items. Some books have taken this marketing scheme even further with titles that begin with '102', '103', or '1001'.\n* Room 101 in George Orwell's novel Nineteen Eighty-Four\n* The year AD 101 or 101 BC.
- See also 101 km
\n\n\n