911 (number)
| ||||
|---|---|---|---|---|
| Cardinal | nine hundred eleven | |||
| Ordinal |
911th (nine hundred and eleventh) | |||
| Factorization | 911 | |||
| Prime | Yes | |||
| Roman numeral | CMXI | |||
| Binary | 11100011112 | |||
| Ternary | 10202023 | |||
| Quaternary | 320334 | |||
| Quinary | 121215 | |||
| Senary | 41156 | |||
| Octal | 16178 | |||
| Duodecimal | 63B12 | |||
| Hexadecimal | 38F16 | |||
| Vigesimal | 25B20 | |||
| Base 36 | PB36 | |||
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 sum of digits and product 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
- AD 911, the year
- 9-1-1, the telephone number of most local emergency agencies in the United States and Canada.
- Porsche 911
References
- ↑ "Sloane's A062786 : Centered 10-gonal numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-06-02.