| ||||
|---|---|---|---|---|
| Cardinal | one hundred ninety-one | |||
| Ordinal | 191st (one hundred ninety-first) | |||
| Factorization | prime | |||
| Prime | 43rd | |||
| Greek numeral | ΡϞΑ´ | |||
| Roman numeral | CXCI | |||
| Binary | 101111112 | |||
| Ternary | 210023 | |||
| Senary | 5156 | |||
| Octal | 2778 | |||
| Duodecimal | 13B12 | |||
| Hexadecimal | BF16 | |||
191 (one hundred [and] ninety-one) is the natural number following 190 and preceding 192.
In mathematics
[edit]191 is a prime number, part of a prime quadruplet of four primes: 191, 193, 197, and 199.[1] Because doubling and adding one produces another prime number (383), 191 is a Sophie Germain prime.[2] It is the smallest prime that is not a full reptend prime in any base from 2 to 10; in fact, the smallest base for which 191 is a full period prime is base 19.[3]
See also
[edit]References
[edit]- ^ Sloane, N. J. A. (ed.). "Sequence A136162 (List of prime quadruplets {p, p+2, p+6, p+8})". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ^ Sloane, N. J. A. (ed.). "Sequence A005384 (Sophie Germain primes p: 2p+1 is also prime)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ^ Wolfram MathWorld; Primitive Root
Well, that’s interesting to know that Psilotum nudum are known as whisk ferns. Psilotum nudum is the commoner species of the two. While the P. flaccidum is a rare species and is found in the tropical islands. Both the species are usually epiphytic in habit and grow upon tree ferns. These species may also be terrestrial and grow in humus or in the crevices of the rocks.
View the detailed Guide of Psilotum nudum: Detailed Study Of Psilotum Nudum (Whisk Fern), Classification, Anatomy, Reproduction