105 (number)

105 is the natural number following 104 and preceding 106. It is the double factorial of 7.

List of numbers — Integers << 100 101 102 103 104 105 106 107 108 109 >>
Cardinal	one hundred [and] five
Ordinal	105th
Factorization
Divisors	3, 5, 7, 15, 21, 35
Roman numeral	CV
Binary	1101001
Hexadecimal	69

In mathematics

One hundred five is a triangular number and a dodecagonal number as well as a sphenic number and a Zeisel number. It comes in the middle of the prime quadruplet (101, 103, 107, 109). The only other such odds less than a thousand are 15, 195 and 825.

One hundred five is also a number n for which is prime, for . (This even works up to , ignoring the negative sign.)

In other fields

One hundred five is also:

• The atomic number of hahnium, also known as dubnium.
• The designation of some spur routes of Interstate 5.
• A film format introduced by Kodak for their first folding camera. See 120_film.
• The year AD 105 or 105 BC.