309 (number)
309 or three hundred nine is the natural number following 308 and preceding 310.{{Infobox number|cardinal=three hundred nine|ordinal=309th
(three hundred ninth)|factorization=3 × 103|divisor=1, 3, 103, 309|roman=CCCIX}}
In mathematics
- 309 is an odd composite number.
- 309 is composed of two distinct prime numbers multiplied (103 and 3).{{Cite web |date=Apr 30, 2024 |title=Numbermatics: The Number Explorer |url=https://www.numbermatics.com |access-date=Apr 30, 2024 |website=Numbermatics}}
- 309 is a Blum integer.{{Cite web |date=Apr 30, 2024 |title=Blum Number |url=https://planetmath.org/blumnumber |access-date=Apr 30, 2024 |website=PlanetMath}}
- 309 is a centered icosahedral number.{{Cite web |last=Sloane |first=N. J. A. |date=May 1, 2024 |title=The On-Line Encyclopedia of Integer Sequences |url=https://oeis.org |access-date=May 1, 2024 |website=OEIS}}