CoinMarketCap has an iOS and Android mobile app!
It features project descriptions, Candlestick charts, daily OHLCV data, portfolio and watchlist, price alerts, conversion calculator, compare crypto, cryptocurrency and blockchain news, top gainers and losers, and more. Its even got a dark mode!
The Android app requires Android 5.0 or later.
The iOS app requires iOS 11.0 or later.