135

135 is a natural number that comes after 134 and before 136. It is an odd composite number with prime factorization 3^3 × 5. Its positive divisors are 1, 3, 5, 9, 15, 27, 45, and 135; the sum of the proper divisors is 105, making it a deficient number.

135 has several common base representations: in binary it is 10000111, in octal 207, and in hexadecimal 0x87. In Roman numerals it is written as CXXXV. The number can also be expressed as the sum of two consecutive integers: 67 and 68.

From a number theory perspective, 135 is divisible by 9 and 3, and it is a Harshad number in base 10 since 1 + 3 + 5 = 9 and 135 ÷ 9 = 15. It is not a triangular or square number, but it is the product of a small prime power and a distinct prime (3^3 × 5).

Geometrically, 135 degrees is the measure of each interior angle in a regular octagon. In the calendar, the 135th day of a non-leap year is May 15; in a leap year it falls on May 14. Historically, the year 135 CE marked the end of the Bar Kokhba revolt and the Roman emperor Hadrian’s reorganization of the province, with Jerusalem renamed and rebuilt as Aelia Capitolina.