189 (number)

189 1, 3, 7, 9, 21, 27, 63, 189 189 (one hundred [and] eighty-nine) is the natural number following 188 and preceding 190. In mathematics 189 is a centered cube numberA005898 Centered cube numbers and a heptagonal number.A000566 Heptagonal numbers The centered cube numbers are the sums of two consecutive cubes, and 189 can be written as sum of two cubes in two ways: 43 + 53 and 63 + (−3)3.A051347 Numbers that are the sum of two (possibly negative) cubes in at least 2 ways The smallest number that can be written as the sum of two positive cubes in two ways is 1729.A001235 Taxi-cab numbers: sums of 2 cubes in more than 1 way The largest prime number that can be represented in 256-bit arithmetic is the "ultra-useful prime" 2256 − 189,A058220 Ultra-useful primes: smallest k such that 2^(2^n) - k is prime used in quasi-Monte Carlo methods Hechenleitner Bernhard Entacher Karl 10.1016/j.cam.2005.03.058 1–2 Journal of Computational and Applied Mathematics 2202988 424–441 A parallel search for good lattice points using LLL-spectral tests 189 2006 free See Table 5. and in some cryptographic systems. Longa Patrick Gebotys Catherine H. Catherine Gebotys Mangard Stefan Standaert François-Xavier Efficient Techniques for High-Speed Elliptic Curve Cryptography 10.1007/978-3-642-15031-9_6 80–94 Springer Lecture Notes in Computer Science Cryptographic Hardware and Embedded Systems, CHES 2010, 12th International Workshop, Santa Barbara, CA, USA, August 17-20, 2010. Proceedings 6225 2010 free 978-3-642-15030-2 See Appendix B. See also The year AD 189 or 189 BC List of highways numbered 189 189 References 1 Category:Integers