# 168 (number)

168 (one hundred [and] sixty-eight) is the natural number following 167 and preceding 169.

 ← 167 168 169 →
Cardinalone hundred sixty-eight
Ordinal168th
(one hundred sixty-eighth)
Factorization23 × 3 × 7
Divisors1, 2, 3, 4, 6, 7, 8, 12, 14, 21, 24, 28, 42, 56, 84, 168
Greek numeralΡΞΗ´
Roman numeralCLXVIII
Binary101010002
Ternary200203
Senary4406
Octal2508
Duodecimal12012

## In mathematics

168 is an even number, a composite number, an abundant number, and an idoneal number.[1]

There are 168 primes less than 1000. 168 is the product of the first two perfect numbers.

168 is the order of the group PSL(2,7), the second smallest nonabelian simple group.

From Hurwitz's automorphisms theorem, 168 is the maximum possible number of automorphisms of a genus 3 Riemann surface, this maximum being achieved by the Klein quartic, whose symmetry group is PSL(2,7).[2] The Fano plane has 168 symmetries.

168 is the largest known n such that 2n does not contain all decimal digits.[3]

168 is the fourth Dedekind number.

168 is also: