- 911 (number)
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911 (nine hundred [and] eleven) is the number following 910 and preceding 912.
911 Cardinal Nine hundred and eleven Ordinal 911th Factorization Prime Roman numeral CMXI Binary 1110001111 Hexadecimal 38F It is a prime number, a Sophie Germain prime and the sum of three consecutive primes (293 + 307 + 311). It is an Eisenstein prime with no imaginary part and real part of the form 3n − 1. Since 913 is a semiprime, 911 is a Chen prime. It is also a centered decagonal number.
There are 911 inverse semigroups of order 7 (sequence A001428 in OEIS)
911 is obtained by concatenating its sum of digits and product of digits.
The Madrid Attack came exactly 911 days after 9/11.
As "911" or "9/11", typically pronounced "nine-eleven", it is commonly used to refer the calendar dates November 9 or September 11, depending on which date notation is used. The latter usage most commonly refers to the September 11, 2001 attacks in the United States.
See also
- 911 C.E., the year
- 9-1-1, the telephone number of most local emergency agencies in the United States and Canada.
References
Categories:- Integers
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