172

172 (one hundred seventy-two) is an even composite number. Its prime factorization is 2^2 × 43, so its positive divisors are 1, 2, 4, 43, 86, and 172. It sits between 169 (13^2) and 196 (14^2).

In numerals, 172 is written as CLXXII in Roman numerals. In other bases, it appears as 10101100_2 in binary, 254_8 in octal, AC_16 in hexadecimal, and 20101_3 in base 3.

In the calendar, the 172nd day of the year corresponds to June 21 in common years and June 20 in leap years.

As a plain integer, 172 is used in counting, labeling, and various numeration systems. There are no widely cited mathematical constants or theorems uniquely associated with 172, but it serves as a straightforward example of a small, composite number with the factorization 2^2 × 43.