node, 79 bytes

Result

WA

Code [DL]

console.log(require('fs').readFileSync('/dev/stdin').split("").sort().join(""))

stdin

2725949887428190890756417835597613682272422611236983320400594256028709887764059118128944002126864547

stdout

stderr

/volume/CODE:1
(function (exports, require, module, __filename, __dirname) { console.log(require('fs').readFileSync('/dev/stdin').split("").sort().join(""))
                                                                                                                   ^

TypeError: require(...).readFileSync(...).split is not a function
    at Object.<anonymous> (/volume/CODE:1:116)
    at Module._compile (module.js:571:32)
    at Object.Module._extensions..js (module.js:580:10)
    at Module.load (module.js:488:32)
    at tryModuleLoad (module.js:447:12)
    at Function.Module._load (module.js:439:3)
    at Module.runMain (module.js:605:10)
    at run (bootstrap_node.js:427:7)
    at startup (bootstrap_node.js:148:9)
    at bootstrap_node.js:542:3

strace