A weird regex (not sure it's really usefull) :

\d{8,}|123456[8-9]|12345[7-9]\d|1234[6-9]\d{2}|123[5-9]\d{3}|12[4-9]\d{4}|1[3-9]\d{5}|[2-9]\d{6}\b

It works only for the number 1234567 you have to modify it for another number.