:287 (number)
{{Infobox number
| number = 287
| divisor = 1, 7, 41, 287
}}
287 is the natural number following 286 and preceding 288.
In mathematics
- 287 is an odd composite number with 2 prime factors.{{Cite web|url=https://mathworld.wolfram.com/CompositeNumber.html|title=Composite numbers|website=mathworld.wolfram.com}}
- 287 is the sum of consecutive primes in three different ways, 89+97+101, 43+53+59+61+67, and 17+19+23+29+31+37+41+43+47
- 287 is a pentagonal number which follows the concept of triangular numbers.{{Cite web|url=https://mathworld.wolfram.com/PentagonalNumber.html|website=mathworld.wolfram.com|title=Pentagonal number}}
- 287 is an odd semiprime number.{{Cite OEIS|A046315|Odd semiprimes: odd numbers divisible by exactly 2 primes (counted with multiplicity)}}
- 287 is the sum of exactly 4 nonzero squares.{{Cite OEIS|A004215|Numbers that are the sum of 4 but no fewer nonzero squares}}
- 287 is a number where 2(287)-1 and 2(287)+1 are both prime.{{Cite OEIS|A002822|Numbers m such that 6m-1, 6m+1 are twin primes}}