129 (one hundred [and] twenty-nine) is the natural number following 128 and preceding 130.

← 128 129 130 →
Cardinalone hundred twenty-nine
Ordinal129th
(one hundred twenty-ninth)
Factorization3 × 43
Divisors1, 3, 43, 129
Greek numeralΡΚΘ´
Roman numeralCXXIX
Binary100000012
Ternary112103
Senary3336
Octal2018
DuodecimalA912
Hexadecimal8116

In mathematics

edit

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]

129 is a centered octahedral number.[3]

In the military

edit

In transportation

edit
  • 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.

In other fields

edit

129 is also:

See also

edit

References

edit
  1. ^ "Sloane's A016105 : Blum integers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-27.
  2. ^ "Sloane's A007770 : Happy numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-27.
  3. ^ Sloane, N. J. A. (ed.). "Sequence A001845 (Centered octahedral numbers (crystal ball sequence for cubic lattice))". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2022-06-02.