297

Number
$297$ (two hundred and ninety-seven) is:


 * $3^3 \times 11$


 * The $6$th Kaprekar number after $1, 9, 45, 55, 99$:
 * $297^2 = 88 \, 209 \to 88 + 209 = 297$


 * The $4$th Kaprekar triple after $1, 8, 45$:
 * $297^3 = 26 \, 198 \, 073 \to 26 + 198 + 073 = 297$


 * The $55$th lucky number:
 * $1, 3, 7, 9, 13, 15, 21, \ldots, 237, 241, 259, 261, 267, 273, 283, 285, 289, 297, \ldots$