That's the # of items in your Second Life inventory's Library folder. At least for now.
How did I find out? Well, today I was helping Jeska Linden do some testing on the Orientation Island, and logged in with a new account to find my inventory totally empty. 
Expanding each folder (and really, empty folders should be unexpandable) I did a search, and it fetched… 893 items. All of them in my Library.
So there you have it, and perhaps it's a curiosity satisfied, for those of you who'd rather not count the long way, or delete the rest of your inventory. to find out. 
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What a lucky number it is! lol Seeing that title, I thought you were talking about Yakuza, Japanese gangsters. .
But why aren't the sculpted textures in the Library, Torley?
The sculpt maps are, but the textures aren't. So now residents who want to try and make a sculptie, like a piece of fruit, such as an apple, can make the shape but not the look as they could on the Beta Grid.
Seems odd to have left those out.
Wow! That means that after I used your Inventory clean out trick (the boxes), I have exactly 64 items in the 'My Inventory' folder and subfolders! YAYZERAMA!
And hey, everybody should do that! It fastens up teleporting to warp speed!
@Seagel: I wasn't previously familiar with that reference, now I must look it up.
@Benja: GOOD question, I don't know why they were removed; perhaps ask Qarl Linden? I know somewhere along the way, the sculpt map texture orientation was changed, but I feel more useful examples would be valuable. I would've liked the whole bowl of fruit to be included in Library's Objects.
@Xara: Nice to know! That's a slim inventory… or a "slimventory" for short. I don't think small inventories are healthier for teleports — wearing no scripted attachments will make for faster TPs — but keeping your items compact certainly is good for our databases.
OK, I have raised a bug about the loss of the sculptie textures from the Library: https://jira.secondlife.com/browse/VWR-883
My vidtut on the sculpted apple has had over 1800 views, and it's a pity that no-one will be able to make it look like an apple without the texture.
Oh! If only I had waited for ten more bugs, I could have made it VWR-893. Spooky