129 (number)

 ← 128 129 130 →
Cardinal one hundred twenty-nine
Ordinal 129th
(one hundred and twenty-ninth)
Factorization 3 × 43
Divisors 1, 3, 43, 129
Roman numeral CXXIX
Binary 100000012
Ternary 112103
Quaternary 20014
Quinary 10045
Senary 3336
Octal 2018
Duodecimal A912
Vigesimal 6920
Base 36 3L36

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: , , , and .

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.[1]

129 is a repdigit in base 6 (333).

129 is a happy number.[2]

In transportation

• LZ 129 Hindenburg was a German zeppelin which went up in flames while landing on May 6, 1937
• London Buses route 129 is a Transport for London contracted bus route in London
• STS-129 was a Space Shuttle mission to the International Space Station, flown in November 2009 by the shuttle Atlantis.

129 is also: