911 (number)

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← 910 911 912 →
Cardinalnine hundred eleven
Ordinal911th
(nine hundred eleventh)
Factorizationprime
PrimeYes
Greek numeralϠΙΑ´
Roman numeralCMXI
Binary11100011112
Ternary10202023
Quaternary320334
Quinary121215
Senary41156
Octal16178
Duodecimal63B12
Hexadecimal38F16
Vigesimal25B20
Base 36PB36

911 (nine hundred [and] eleven) is the integer following 910 and preceding 912.

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.[1]

There are 911 inverse semigroups of order 7 (sequence A001428 in the OEIS)

911 is obtained by concatenating its product of digits and sum of digits.

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 North American emergency telephone number, see 9-1-1, or the September 11, 2001 attacks in the United States.

See also[edit]

References[edit]

  1. ^ Sloane, N. J. A. (ed.). "Sequence A062786 (Centered 10-gonal numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-02.