In mathematics

• The number 1289 is called an apocalyptic power because 2¹²⁸⁹ contains the consecutive digits 666 (in decimal), as the Number of the Beast
  Number of the Beast
  The Number of the Beast is a term in the Book of Revelation, of the New Testament, that is associated with the first Beast of Revelation chapter 13, the Beast of the sea. In most manuscripts of the New Testament and in English translations of the Bible, the number of the Beast is...
  
  : in the sequence ..., 1281, 1285, 1286, 1289, 1290, 1298, 1301, etc.

• The number 1289 is classed as a deficient number
  Deficient number
  In number theory, a deficient number or defective number is a number n for which the sum of divisors σIn number theory, a deficient number or defective number is a number n for which the sum of divisors σIn number theory, a deficient number or defective number is a number n for which...
  
   because the sum of all its positive divisors (except itself) totals less than 1289. Compare with perfect and abundant numbers.

• The number 1289 is classed as an evil number because it has an even number of 1's contained in its binary expansion.

In technology

• 1289 is a 4.5 volt battery
  Battery (electricity)
  An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...
  
  with 3 cells in flat side-by-side format with brass-strip connections, also known as MN1203, 3LR12 and many other "R12" variations.