210

Number
$210$ (two hundred and ten) is:


 * $2 \times 3 \times 5 \times 7$


 * The $4$th primorial, after $1, 2, 6, 30$ (counting $1$ as the zeroth):
 * $210 = 7 \# = 2 \times 3 \times 5 \times 7$
 * Hence the smallest positive integer with $4$ distinct prime factors.


 * The $7$th pentatope number after $1, 5, 15, 35, 70, 126$:
 * $210 = 1 + 4 + 10 + 20 + 35 + 56 + 84 = \dfrac {7 \left({7 + 1}\right) \left({7 + 2}\right) \left({7 + 3}\right)} {24}$


 * The $11$th number after $1, 3, 22, 66, 70, 81, 94, 115, 119, 170$ whose $\sigma$ value is square: