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1987 (number)

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Natural number
← 1986 1987 1988 →
← 0 1k 2k 3k 4k 5k 6k 7k 8k 9k →
Cardinalone thousand nine hundred eighty-seven
Ordinal1987th
(one thousand nine hundred eighty-seventh)
Factorizationprime
Prime300th
Greek numeral,ΑϠΠΖ´
Roman numeralMCMLXXXVII
Binary111110000112
Ternary22011213
Senary131116
Octal37038
Duodecimal119712
Hexadecimal7C316

1987 is the natural number following 1986 and preceding 1988.

In mathematics

1987 is an odd number and the 300th prime number. It is the first number of a sexy prime triplet (1987, 1993, 1999). Being of the form 4n + 3, it is a Gaussian prime. It is a lucky number and therefore also a lucky prime. 1987 is a prime factor of the 9th number in Sylvester's sequence, and is the 15th prime to divide any number in the sequence.

There are 1987 polyiamonds with 12 cells that tile the plane isohedrally.

In other fields

  • There are 1987 ways to place four non-attacking chess kings on a 5 × 5 board.

References

  1. (sequence A075223 in the OEIS).
  2. (sequence A061997 in the OEIS).


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