Misplaced Pages

154 (one hundred fifty-four) is the natural number following 153 and preceding 155.

In mathematics

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 ${\displaystyle 0!}$ and assumes that ${\displaystyle 0!=1}$.

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

1. "Sloane's A001106 : 9-gonal (or enneagonal or nonagonal) numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-28.
2. "Sloane's A000124 : Central polygonal numbers (the Lazy Caterer's sequence)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-28.

• Wells, D. The Penguin Dictionary of Curious and Interesting Numbers London: Penguin Group. (1987): 140 - 141

External links

• Virtual Science: Number 154 Archived 2017-06-30 at the Wayback Machine

• Integers