169 (one hundred [and] sixty-nine) is the natural number following 168 and preceding 170.
In mathematics
169 is an odd number, a composite number, and a deficient number.
169 is a square number: 13 × 13 = 169, and if each number is reversed the equation is still true: 31 × 31 = 961. 144 shares this property: 12 × 12 = 144, 21 × 21 = 441.
169 is one of the few squares to also be a centered hexagonal number. Like all odd squares, it is a centered octagonal number. 169 is an odd-indexed Pell number, thus it is also a Markov number, appearing in the solutions (2, 169, 985), (2, 29, 169), (29, 169, 14701), etc. 169 is the sum of seven consecutive primes: 13 + 17 + 19 + 23 + 29 + 31 + 37. 169 is a difference in consecutive cubes, equaling
In astronomy
169 Zelia is a bright main belt asteroid
Gliese 169 is an orange, main sequence (K7 V) star in the constellation Taurus
QSO B0307+169 is a quasar in the constellation Aries
Sayh al Uhaymir 169 is a 206g lunar meteorite found in Sultanate of Oman
In the military
was a United States Navy technical research ship during the 1960s
was a United States Navy during World War II
was a United States Navy during World War II
was a United States Navy following World War I
was a United States Navy during World War II
was a United States Navy submarine during World War II
169th Battalion, CEF unit in the Canadian Expeditionary Force during the World War I 169th Fires Brigade the US Army National Guard artillery brigade, a part of the Colorado Army National Guard The United States Air Force's 169th Fighter Wing fighter unit at McEntire Joint National Guard Station, South Carolina 169 or 169th Squadrons 169th Airlift Squadron, a unit of the U.S. Air Force Marine Light Attack Helicopter Squadron 169, United States Marine Corps Light Attack Helicopter Squadron No. 169 Squadron RAF, a unit of the United Kingdom Royal Air Force
In transportation
Metro Transit Route 169 in Seattle
169th Street station on the IND Queens Boulevard Line of the New York City Subway served by the and trains 169th Street was a station on the demolished IRT Third Avenue Line of the New York City Subway
In TV and radio
The IEC 169-2 connector TV aerial plug
In other fields
169 is also: The year AD 169 or 169 BC The atomic number of an element temporarily called Unhexennium 169 is the number of nonequivalent starting hands in the card game Texas hold 'em 169 is known in the computing world as the first number of an automatic IPv4 address assigned by TCP/IP when no external networking device is contactable Minuscule 169 is a Greek minuscule manuscript of the New Testament, on parchment