46 (number)

46 46(forty-six) is the natural number following 45 and preceding 47.

Forty-six is

• thirteenth discrete semiprime (${\displaystyle 2\times 23}$) and the eighth of the form (2.q), where q is a higher prime,
• with an aliquot sum of 26; a semiprime, in an aliquot sequence of six composite numbers (46, 26,16, 15, 9, 4, 3, 1, 0) in the prime 3-aliquot tree,
• a Wedderburn-Etherington number,^[1]
• the second non-trivial enneagonal number, after 24,^[2]
• a centered triangular number,^[3]
• the number of parallelogram polyominoes with 6 cells.^[4]
• the amount of prime numbers in between 1 and 200.

It is the sum of the totient function for the first twelve integers.^[5] 46 is the largest even integer that cannot be expressed as a sum of two abundant numbers. It is also the sixteenth semiprime.^[6]

Since it is possible to find sequences of 46+1 consecutive integers such that each inner member shares a factor with either the first or the last member, 46 is an Erdős–Woods number.^[7]

The friendly giant ${\displaystyle \mathbb {F_{1}} }$, the largest of twenty-six sporadic groups, holds a total of forty-six maximal subgroups.^[a]

• The number of mountains in the 46 peaks of the Adirondack mountain range. People who have climbed all of them are called "forty-sixers"; there is also an unofficial 47th peak.^[9]

Forty-six is also:

• Because 46 in Japanese can be pronounced as "yon roku", and "yoroshiku" (よろしく) means "my best regards" in Japanese, people sometimes use 46 for greeting.