This Wikipedia page on ΙΧΘΥΣ states that Augustine noted that:

> the generating sentence " Ἰησοῦς Χριστὸς [sic] Θεοῦ Υἱὸς Σωτήρ" has 27 letters, i.e. 3 x 3 x 3, which in that age indicated power. (This suggestion is obviously spurious, resulting from Augustine's ignorance of Greek.)

I don't follow how the number 27 arises from bad Greek (rather, it would appear, bad counting).

The Bagatti reference provided does not appear to be available online. Any ideas?

@Susan Well, bad something: it seems he's conflating the Greek sentence with a (quasi?) Latin form, so "ch" still counts as "1", but it isn't Χριστὸς but "chreistos" (so there's the extra letter). This is confirmed by the acrostic he cites. The Bettenson (Penguin) translation in City of God keeps it all in Latin, in fact.

Compare, however, Peter Brown's assessment in his (justly) famous biography of Augustine, p. 24. (The bio is very well written: well worth a read. Airplane book?)