Mersenne prime Mersenne prime In mathematics, a Mersenne prime is a prime number that is one less than a power of two. That is, it is a prime number of the form for some integer . They are named after Marin Mersenne, a French Minim friar, who studied them in the early 17th century. The exponents which give Mersenne primes are 2, 3, 5, 7, 13, 17, 19, 31, ... and the resulting Mersenne primes are 3, 7, 31, 127, 8191, 131071, 524287, 2147483647, ... . If is a composite number then so is . ( is divisible by both and .)
11 (number) 11 (number) 11 (eleven) is the natural number following 10 and preceding 12. It is the first repdigit. In English, it is the smallest positive integer requiring three syllables and the largest prime number with a single-morpheme name. Eleven derives from the Old English ' which is first attested in Bede's late 9th-century "Ecclesiastical History of the English People". It has cognates in every Germanic language (for example, German "elf"), whose Proto-Germanic ancestor has been reconstructed as *"ainalifa-", from the prefix *"aina-" (adjectival "one") and suffix *"-lifa-" of uncertain meaning. It is sometimes compared with the Lithuanian ', although ""