## Monday, August 9, 2010

### 513

513 = 33 x 19.

513 is 1000000001 in base 2 and 1001 in base 8. It is 20001 in base 4 and 201 in base 16.

513 is a sum of two positive cubes: 513 = 83 + 13.

513 appears in the sequence generated when you start with 1 and repeatedly reverse the digits and add 16 to get the next term.

513 are the first three digits in the Dewey Decimal Classification System call numbers for library books in arithmetic.

#### 1 comment:

Anonymous said...

Other properties of the number 513
513 is a Harshad number as 513/(5+1+3) = 57
513=2^9+1
513 divides 2^18-1
513 is a number Hexagodecagonal since (14n^2-12n)/2=513 with n= 9
513=11^2+14^2+14^2=12^2+12^2+15^2
513 can be represented as Pythagorean triples
513^2+1584^2=1665^2
513^2+131584^2=131585^2
513 If you add or subtract 10, are two prime numbers (503.523}
513 is the sum of an exponent with base 2 and a prime number
513=2^6+449=2^8+257
513 can be represented as the sum of a square and a prime number
513=2^2+509=14^2+317=20^2+113=22^2 +29
Rafael Parra Machio