You can use the as.numeric function to convert the column to numbers but I expect you will get a warning "NAs introduced by coercion" because something in that column does not look like a number to R. You can find what that is like this (I will assume your tibble is called DF):
VALS <- DF$ADR
NUMs <- as.numeric(VALS) #you should get the warning here
BadLocations <- which(is.na(NUMs))
BadLocations #this will tell you what row(s) the bad values are in
BadVals <- VALS[BadLocations]
BadVals
Once you know what is preventing the column from being read as numbers, you can delete it or replace it or let the as.numeric function convert it to NA.
DF$ADR <- as.numeric(DF$ADR)