Author Yann Martel definitely chose 227 for the number of days aboard the lifeboat for the very reason you mention (22/7 = ~pi). And it's worthwhile to consider what this means, what it suggests, for instance, about how Pi's 227-day journey came to define him--approximately (significantly, 22/7 is rational, whereas pi is not). It's also interesting to consider what this suggests about various themes in the novel--the nature of coincidence, meaning-making, belief/faith, story, order. As for order, the 227-day journey reminds me of the 100-chapter structure of the novel, which adult Pi ponders as a perhaps-possible, perfectly-pleasing structure for his story; Pi, it seems, here and elsewhere in the novel, is interested in the relationship between the infinite and the bound, the rational and the irrational.
This small detail (227 days) is one of many in the novel that become meaningful when we attend on multiple levels--to layers of meaning (literal and figurative), and to both detail and the bigger picture. It reminds us that there is an intelligence (an author) at play behind the story and that meaning is there to be found for the open and astute reader, as it was for Pi.
I hope that's some good food for thought...