cat file.txt | awk '{print $1*1000000}'

awk '{print $1*1000000}' file.txt

expr $var * 1000000

while read line; do
  if [ ! -z $line ]; then
    echo -e $line"t"$(expr $line * 1000000)
  fi
done <inputfile.txt

213
654
34
67

213 213000000
654 654000000
34  34000000
67  67000000