1769

1769 = 29 x 61.

1769 is a semiprime of the special form: the sum of a semiprime k and the kth semiprime (A100467).

1769 is a centered tridecagonal number (A069126).

The square of 1769 is the sum of three consecutive primes (A076304).

The 1769th triangular number (1,565,565) contains only the digits 1, 5, and 6 (A119133).

1769 has two representations as a sum of two squares: 1769 = 13² + 40² = 20² + 37².

1769 is the hypotenuse of two primitive Pythagorean triples: 1769² = 696² + 1480² = 1040² + 1431².

1769 divides 88¹⁰ - 1.

Source: On-Line Encyclopedia of Integer Sequences