The Hebrew word eleph means "thousand" (BDB 48, KB 59 II). It is used in several senses in the OT.
a family unit, Josh. 22:14; Jdgs. 6:15; 1 Sam. 23:23; Zech. 9:7; 12:6
a military unit, Exod. 18:21,25; Num. 13:14; Deut. 1:15
a literal thousand, Gen. 20:16; Exod. 32:28; Num. 35:4; Neh. 3:13
a symbolic number, Gen. 24:60; Exod. 20:6; 34:7; Deut. 7:9; Josh. 23:10; Ps. 50:10; 90:4; 119:72; Eccl. 6:6; Jer. 32:18; 2 Pet. 3:8
the Ugaritic cognate alluph means "chieftain" (i.e., a military or political designation), Gen. 36:15
These different connotations cause modern interpreters to question the literalness of the numbers
of the exodus (see Special Topic below)
of Israeli tribal military units (i.e., 1 Chr. 12:35)
Remember, literalness is not the key to Bible interpretation, but rather the intent of the original, inspired author and his choice of lexical options.