Oracle Regexp Query

Hi guys, wonder if anyone can help.

I am looking to highlight any rows which contain non numeric characters in a specific field.

ie.
123456789 - valid
987456321 -valid
147852369 - valid
ABC123456 - invalid
DEF789 - Invalid
78DE47F1 - Invalid.

I am trying to use an Oracle regular expression to identify the invalid rows

I have tried

REGEXP_LIKE(field, ‘[[:digit:]]’))

and

REGEXP_LIKE(field, ‘[[:alpha:]]’))

but with no luck.

Appreciate any help.

Regards,
Liam