length property in built-in Object, Number

Why does the built-in Object, Number, have a length property?

var n = Number;
n;

EPSILON: 2.220446049250313e-16
MAX_SAFE_INTEGER: 9007199254740991
MAX_VALUE: 1.7976931348623157e+308
MIN_SAFE_INTEGER: -9007199254740991
MIN_VALUE: 5e-324
NEGATIVE_INFINITY: -Infinity
NaN: NaN
POSITIVE_INFINITY: Infinity
isFinite: ƒ isFinite()
isInteger: ƒ isInteger()
isNaN: ƒ isNaN()
isSafeInteger: ƒ isSafeInteger()
length: 1 // For what??