What does "イタズラ書きだらけの壁にひとつの携帯番号." mean?


I am around N5 level (almost finished book that is a little bit over this
level) and so I decided to try learning some life language translating manga
from raw and checking it in a translated version. I use Noragami and it's my
first day so the beginning. I found a sentence that is translated very
differently than I did it with me not understanding why so if anyone could
clarify what it literally says, I'd be grateful.

イタズラ書きだらけの壁にひとつの携帯番号。

If it helps: furigana for first kanji is ga, then it's kabe, at the end it's
keetaibangou.

I kinda understand that it should end with something connected to a mobile
phone number, probably a lone one/only one and that there is an inscription on
a wall. But I cannot understand those katakana and then hiragana parts and I
cannot connect it into one sentence.  
Thanks a lot for help.




I think your interpretation of the sentence, **_a lone one/only one and that
there is an inscription on a wall._** , is close.

I think 「イタズラ書きだらけ」is compound. It is strange to drop one word in the phrase.

So, do you want to parse the sentence a little bit for understanding the mix
of ひらがな and カタカナ?

> ((イタズラ + 書き) + だらけ) + の + 壁 + に + ひとつ + の + 携帯番号。

[イタズラ書き](https://kotobank.jp/word/%E6%82%AA%E6%88%AF%E6%9B%B8%E3%81%8D%E3%83%BB%E5%BE%92%E6%9B%B8%E3%81%8D-203653)
means _Doodles/graffiti/sketches,etc._

[だらけ](https://kotobank.jp/word/%E3%81%A0%E3%82%89%E3%81%91-563186) means
_(something like unnecessary stuff) scattered about, full of (often used
negatively)_ and the suffix to noun

「イタズラ書きだらけ」 Doodles/graffiti/sketches,etc. are spread out/scattered about.

> イタズラ書きだらけの壁にひとつの携帯番号。

_There's one/lone mobile phone number on the wall (about) which
Doodles/graffiti/sketches,etc. are scattered (about)/spread out._

