2211

Number
$2211$ (two thousand, two hundred and eleven) is:
 * $3 \times 11 \times 67$


 * The $66$th triangular number after $1$, $3$, $6$, $10$, $15$, $\ldots$, $1326$, $1378$, $1431$, $1485$, $1540$, $1596$, $1653$, $1711$, $1770$, $1770$, $1830$, $1891$, $1953$, $2016$, $2080$, $2145$:
 * $2211 = \ds \sum_{k \mathop = 1}^{66} k = \dfrac {66 \times \paren {66 + 1} } 2$