6670

Number
$6670$ (six thousand, six hundred and seventy) is:


 * $2 \times 5 \times 23 \times 29$


 * The $58$th hexagonal number after $1$, $6$, $15$, $28$, $45$, $66$, $91$, $\ldots$, $4005$, $4186$, $4371$, $4560$, $4950$, $5151$, $5356$, $5565$, $5778$, $5995$, $6216$, $6441$:
 * $6670 = \ds \sum_{k \mathop = 1}^{58} \paren {4 k - 3} = 58 \paren {2 \times 58 - 1}$


 * The $115$th triangular number after $1$, $3$, $6$, $10$, $15$, $\ldots$, $5995$, $6105$, $6216$, $6328$, $6441$, $6555$:
 * $6670 = \ds \sum_{k \mathop = 1}^{115} k = \dfrac {115 \times \paren {115 + 1} } 2$