In the following verse each digit represents a letter, the same letter throughout, of course. And to help you the letters represented by 123456789 for a word.
2 1763861 3 17638. 3 761-532761 8321 of 16779
Said 831 38 2; let none who 5637 167216
In 839 3821 456 56345 I've oft 8316 86779 -
45676 389, 2 and 1637 old 53779 5216.
The word is DIATHERMY making the rhyme
I dreamed a dream. A red-haired maid of Derry
Said mad am I; let none who hear deride
In May amid the heath I've oft made merry -
There Amy, I and dear old Harry hide.