In decimal, the number is 6830770643, which happens to be a prime number. And in binary, it is a palindrome.
That combination of facts seems unusual enough that I have a difficult time believing that a call wasn't made to someone over in the Faculty of Mathematics building to suggest an interesting number.
Johnston does, after all, have unique access to a whole building devoted to mathematicians. Specifically, the Faculty of Mathematics, at University of Waterloo In particular, the Pure Mathematics department is all about discovering beautiful mathematical patterns. They don't purely spend their days "doing this," but it sure is the kind of thing I would expect of them.
Prime numbers are certainly interesting, as they have been applied to such diverse purposes as cryptography (see RSA), hashing, generation of random numbers, and are used at the root of Godel's proof of incompleteness. To a pure mathematician, if a number is prime, that's interesting.
It's not impossible that there is some additional Cool Meaning to be found if one reassembles the bits in some other form. (It would be neat if, in ASCII, it represented the date when some department or faculty at University of Waterloo opened.) But "palindromic prime" is pretty sufficient to make it interesting, and Johnston has an easy walk over to a place where he can find a group of mathematicians capable of pulling that out of their hats.