56

Number
$56$ (fifty-six) is:


 * $2^3 \times 7$


 * The $6$th tetrahedral number, after $1, 4, 10, 20, 35$:
 * $56 = 1 + 3 + 6 + 10 + 15 + 21 = \dfrac {6 \left({6 + 1}\right) \left({6 + 2}\right)} 6$


 * The $13$th semiperfect number after $6, 12, 18, 20, 24, 28, 30, 36, 40, 42, 48, 54$:
 * $56 = 1 + 2 + 4 + 7 + 14 + 28$


 * The $1$st element of the $3$rd pair of integers $m$ whose values of $m \tau \left({m}\right)$ is equal:
 * $56 \times \tau \left({56}\right) = 448 = 64 \times \tau \left({64}\right)$