1000 (number) - in Mathematics

In Mathematics

• The decimal representation for one thousand is
  • 1,000—a one followed by three zeros, in the general notation ;
  • 1 × 103—in engineering notation, which for this number coincides with :
  • 1 × 103 exactly—in scientific normalized exponential notation ;
  • 1 E+3 exactly—in scientific E notation.
• The SI prefix for a thousand is kilo-, officially abbreviated as k—for instance prefixed to "metre" or its abbreviation m, kilometre or km signifies a thousand metres, as such, technically oriented people occasionally represent the number in a non-standard notation by replacing the last three zeros of the general numeral with "k", for instance, 30k for 30,000.
• By the SI writing style, a comma or a space can be used to as a Thousands separator, i.e., to separate the digits of a number every power of 1000.
• The sum of Euler's totient function over the first 57 integers is 1000.
• Prime Curios! mentions that 1000 is the smallest number that generates three primes in the fastest way possible by concatenation of decremented numbers (1000999, 1000999998997, and 1000999998997996995994993 are prime). The criterion excludes counting the number itself.