Seperating numbers from alphanumeric field using regex

Question

How to seperate the number from this string using regex

4645sgdfghdf - 4645
sdfd544545 - 544545
54sdfsdfsdf -...
fdsfd54556 -...
wetregdfg859665 - ...
56453546dfghff - ....
251fdgfdg6 - 2516

Any help is much appreciated.. Thanks in advance