810 = 2 x 34 x 5.
810 has a representation as a sum of two squares: 810 = 92 + 272.
810 has the representation 36 + 81.
810 is a value of n for which n - 1 (809) and n + 1 (811) are twin primes, and so are 2n - 1 (1619) and 2n + 1 (1621).
810 is 1100 in base 9.
Other features of the number 810
ReplyDelete810 is a Harshad number since it is divisible by the sum of its prime factors
810/(2+3+5)=81,see A005349
810 is divisible by 91^9-1
810 can be represented
810=5^2+16^2+23^2
810=7^2+19^2+20^2
810=9^2+3^6=3^4+3^6
810=3^3+3^3+3^3+9^3
810 can be represented as Pythagorean triples
810^2=486^2+648^2
810^2+164024^2=164026^2
810^2+504^2=954^2
810^2+1944^2=2106^2
810^2+6536^2=6586^2
810 may be represented as the sum of a square and a prime number
It can also be represented as a square but the product of 3^2 by an integer
810=3^2+89*3^2=21^2+41*3^2=15^2+65*3^2
Or the difference between a square and the product of an integer by 3^2
810=30^2-10*3^2=33^2-31*3^2=39^2-79*3^2
810=1^2+809=7^2+761=13^2+641
810=17^2+521=19^2+449=23^2+281
Or as opposed to a square and a prime number
810=29^2-31=31^2-151=43^2-1039
810=47^2-1399=53^2-1999
Rafael Parra Machio