2005 is a semiprime that is the sum of four successive semiprimes (A158339).
2005 = 1 + 2 x 31 + 3 x 32 + 4 x 33 + 5 x 34 + 6 x 35 (A113531).
2005 has two representations as a sum of two squares: 2005 = 182 + 412 = 222 + 392.
2005 is the hypotenuse of two primitive Pythagorean triples: 20052 = 10372 + 17162 = 13572 + 14762.
2005 is a divisor of 988 - 1.
2005 and the square of 2005 use only the digits 0, 2, 4, and 5 (A136897).
2005 is considered a vertically symmetric number (A053701).
Source: On-Line Encyclopedia of Integer Sequences
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