169 (number)
title: "169 (number)" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["integers"] topic_path: "general/integers" source: "https://en.wikipedia.org/wiki/169_(number)" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::data[format=table title="Infobox number"]
| Field | Value |
|---|---|
| number | 169 |
| divisor | 1, 13, 169 |
| :: |
| number = 169 | divisor=1, 13, 169
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 8^3-7^3.
In other fields
- 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.
References
References
- "Sloane's A003215 : Hex (or centered hexagonal) numbers". OEIS Foundation.
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