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129 (number)
129 (one hundred ndtwenty-nine) is the natural number following 128 and preceding 130. In mathematics 129 is the sum of the first ten prime numbers. It is the smallest number that can be expressed as a sum of three squares in four different ways: 11^2+2^2+2^2, 10^2+5^2+2^2, 8^2+8^2+1^2, and 8^2+7^2+4^2. 129 is the product of only two primes, 3 and 43, making 129 a semiprime. Since 3 and 43 are both Gaussian primes, this means that 129 is a Blum integer. 129 is a repdigit in base 6 (333). 129 is a happy number. 129 is a centered octahedral number. In the military * Raytheon AGM-129 ACM (Advanced Cruise Missile) was a low observable, sub-sonic, jet-powered, air-launched cruise missile used by the United States Air Force * Soviet submarine K-129 (1960) was a Soviet Pacific Fleet nuclear submarine that sank in 1968 * was a United States Navy ''Mission Buenaventura''-class fleet oilers during World War II * was a ''Crosley-class high speed transport of the United States Nav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Number
In mathematics, the natural numbers are those numbers used for counting (as in "there are ''six'' coins on the table") and ordering (as in "this is the ''third'' largest city in the country"). Numbers used for counting are called ''cardinal numbers'', and numbers used for ordering are called ''ordinal numbers''. Natural numbers are sometimes used as labels, known as '' nominal numbers'', having none of the properties of numbers in a mathematical sense (e.g. sports jersey numbers). Some definitions, including the standard ISO 80000-2, begin the natural numbers with , corresponding to the non-negative integers , whereas others start with , corresponding to the positive integers Texts that exclude zero from the natural numbers sometimes refer to the natural numbers together with zero as the whole numbers, while in other writings, that term is used instead for the integers (including negative integers). The natural numbers form a set. Many other number sets are built by succ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
