1765

1765 =  5 x 353. It is a number with exactly two palindromic prime factors (A046368).

1765 is one more than a perfect square (A002522 and A134406).

1765 is the smallest positive number that can be written as the sum of distinct Fibonacci numbers in 39 ways (A013583).

1765 has two representations as a sum of two squares: 1765 = 1² + 42² = 26² + 33².

1765 is the number of polyominoes without holes consisting of six regular unit 13-gons (A103472).

1765 is the hypotenuse of two primitive Pythagorean triples: 1765² = 84² + 1763² = 413² + 1716².

1765 divides 42⁴ - 1.

Source: On-Line Encyclopedia of Integer Sequences