158 (one hundred [and] fifty-eight) is the natural number following 157 and preceding 159. 158 is a nontotient, since there is no integer with 158 coprimes below it. 158 is a Perrin number, appearing after 68, 90, 119. [1] 158 is the number of digits in the decimal expansion of 100!, the product of all the natural numbers up to and including 100.