12,345,678,901,234,567,891

Number
$12 \, 345 \, 678 \, 901 \, 234 \, 567 \, 891$ is:


 * The $2$nd of the only $3$ known prime numbers consisting of strings of consecutive ascending digits starting from $1$ (allowing either $0$ or $1$ to follow $9$)

Also see