1933

1933 is a prime number.

1931 and 1933 form a twin prime pair.

1933 is centered heptagonal number (A069099).

1933 = (1⁹ + 2⁸ + 3⁷ + 4⁶ + 5⁵)/5.

1933 has a representation as the sum of two squares: 1933 = 13² + 42².

1933 is the hypotenuse of a primitive Pythagorean triple: 1933² = 1092² + 1595².

1933 divides 10²¹ - 1.

Source: Prime Curios!