Unix time has historically been encoded as a signed 32-bit integer, a data type composed of 32 binary digits (bits) which represent an integer value, with 'signed' meaning that one bit is reserved to indicate sign (+/–). Thus, a signed 32-bit integer can only represent integer values from −(231) to 231 − 1 inclusive. Consequently, if a signed 32-bit integer is used to store Unix time, the latest time that can be stored is 231 − 1 (2,147,483,647) seconds after epoch, which is 03:14:07 on Tuesday, 19 January 2038.[4] Systems that attempt to increment this value by one more second to 231 seconds after epoch (03:14:08) will suffer integer overflow, inadvertently flipping the sign bit to indicate a negative number.