536,870,911/Historical Note

Historical Note on $536 \, 870 \, 911$
$536 \, 870 \, 911$ was the $4$th Mersenne number that was demonstrated to be composite.

This was done in $1732$ by, who demonstrated it had the divisors $233$ and $1103$.

It is in fact the $3$rd Mersenne number in sequence to be composite.

However, the status of the $4$th such composite Mersenne number, $137 \, 438 \, 953 \, 471$, had been established by in $1640$.