I have a field in an oracle db of datatype VARCHAR2(24) (alphanumeric)

I amy trying to extract records where the above field is a 6 digit numeric

e.g.

168497 I need this
568478 I need this
SWTA-HGT Don't need this
12476 Don't need this

In MS Access (gawdblessit), you can use the '#' wildcard to identify numerics. Any such wildcard in Oracle?

Cheers