272,400,600

Number
$272 \, 400 \, 600$ is:


 * $2^3 \times 3 \times 5^2 \times 107 \times 4243$


 * The index of the $1$st harmonic number to be greater than $20$:
 * $H_{272 \, 400 \, 600} = \ds \sum_{k \mathop = 1}^{272 \, 400 \, 600} \frac 1 k \approx 20 \cdotp 00000 \, 00016$

Also see

 * First Harmonic Number to exceed 20