That depends on what the other number is. You need at least two numbers to find a GCF.
1000 does not divide equally into 689.
1000 meters is equal to 1 kilometer
The GCF is 1000.
The GCF is 125.
The GCF is 2.
The GCF is 100.
The GCF is 1.
The GCF is 2.
The GCF is 4.
The GCF is 1.
The GCF is 5.
The GCF is 1.