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129 (number)

Natural number

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complete sections 5.68
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Words
56
Native text
542 characters
Dictionary match
91%
Revision
1335700670 · 2026-01-30T18:34:28Z
Key vocabulary

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number4 uses in this article twenty-nine1 uses in this article octahedral1 uses in this article different1 uses in this article expressed1 uses in this article following1 uses in this article preceding1 uses in this article semiprime1 uses in this article centered1 uses in this article Gaussian1 uses in this article repdigit1 uses in this article hundred1 uses in this article integer1 uses in this article natural1 uses in this article numbers1 uses in this article product1 uses in this article making1 uses in this article first1 uses in this article happy1 uses in this article means1 uses in this article

Overview

129 (one hundred and twenty-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.

Ideas & learning

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