Since none of the previous answers use tidyr::separate
here it goes:
library(tidyr)
df <- data.frame(mycol = c("APPLE348744", "BANANA77845", "OATS2647892", "EGG98586456"))
df %>%
separate(mycol,
into = c("text", "num"),
sep = "(?<=[A-Za-z])(?=[0-9])"
)