189

Number
$189$ (one hundred and eighty-nine) is:


 * $3^3 \times 7$


 * The $9$th heptagonal number after $1, 7, 18, 34, 55, 81, 112, 148$:
 * $189 = 1 + 7 + 11 + 16 + 21 + 26 + 31 + 36 + 41 = \dfrac {9 \left({5 \times 9 - 3}\right)} 2$


 * The $36$th lucky number:
 * $1, 3, 7, 9, 13, 15, 21, \ldots, 133, 135, 141, 151, 159, 163, 169, 171, 189, \ldots$