172 (number)

172 (one hundred and seventy-two) is the natural number following 171 and preceding 173.

Although a noncototient, 172 is the sum of Euler's totient function φ("x") over the first twenty-three integers.

172 is a repdigit in base 6 (444).

* In aviation, and in particular in the aviation-frequency radio exchange (pronounced as "one-seventy-two"), the number 172 is associated with Cessna 172.

"For the year, see 172 AD."

also, Jon Persinger's racing numbersmx and rally racing