HTC J Butterfly has a pixel density of:
440.58

A.K.A. Droid DNS (on Verizon)
Released: 2012

Resolution: 1080×1920 5″ display

Totaling 2.07mp (megapixels) and having a PPI of 440.58

Category: Phone
Tags: htc, android, hd, 1080p, snapdragon, droid

HTC Butterfly

Manufacturer	HTC
Compatible networks	Droid DNA: dual-band CDMA2000 EV-DO Rev. A 800 1900 MHz LTE 700 MHz quad-band GSM, UMTS 850 900 1900 2100 MHz J Butterfly: quad-band GSM, UMTS 850 900 1900 2100 MHz, LTE
Related	Oppo Find 5 ZTE Grand S
Form factor	Bar
Dimensions	143 mm (5.6 in) H 71 mm (2.8 in)W 9.1 mm (0.36 in) D[1]
Mass	140 g (4.9 oz) (HTC Droid DNA)[2]
Operating system	Android 4.4.2 KitKat[1]
System on chip	Snapdragon S4 Pro
CPU	Quad-core 1.5 GHz “Krait” APQ8064 processor[3]
Memory	2 GB RAM[4]
Storage	16 GB internal[4]
Removable storage	Expandable up to 32 GB with microSD (J Butterfly only)
Battery	2020 mAh[4]
Display	5 inch “Super LCD 3″ display 1920×1080 pixels (441 ppi)[3]
Rear camera	8 MP, FullHD 1080p video recording at 30 FPS with re-invented zoom[4]
Front camera	2.1 MP, HD 720p video recording at 30 FPS[4]
Connectivity	Bluetooth 4.0, WiFi, NFC, DLNA, FeliCa, infrared[4]
Website	(HTL21) http://www.htc.com/jp/smartphones/htl21

This righthand infobox courtesy of Wikipedia.