TL left this out, likely cos they're not yet familiar with functionality of furigana, but the wordplay in the phone number Nadeshiko calls is:
10 (ten, as in the english word) 5 (go) 9 (ku) = tengoku / heaven
4 (shi) 2 (ni) ** (gami) = shinigami / grim reaper (although I don't know if "ga/mi" is something JP bros call the asterisk by or if they're just referring to numbers that would've been there)