154 is a
nonagonal number. Its factorization makes 154 a
sphenic number. There is no integer with exactly 154 coprimes below it, making 154 a
noncototient, nor is there, in base 10, any integer that added up to its own digits yields 154, making 154 a
self number 154 is the sum of the first six
factorials, if one starts with 0! and assumes that 0!=1. With just 17 cuts, a pancake can be cut up into 154 pieces (
Lazy caterer's sequence). The distinct prime factors of 154 add up to 20, and so do the ones of 153, hence the two form a
Ruth-Aaron pair. 154! + 1 is a
factorial prime. ==References==