167 (number)
title: "167 (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/167_(number)" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::data[format=table title="Infobox number"]
| Field | Value |
|---|---|
| number | 167 |
| factorization | prime |
| prime | 39th, chen, gaussian, safe |
| divisor | 1, 167 |
| :: |
| number = 167 | factorization=prime | prime = 39th, chen, gaussian, safe | divisor=1, 167
167 (one hundred [and] sixty-seven) is the natural number following 166 and preceding 168.
In mathematics
167 is the 39th prime number, an emirp, an isolated prime, a Chen prime, a Gaussian prime, a safe prime, and an Eisenstein prime with no imaginary part and a real part of the form 3n - 1.
167 is the smallest number which requires six terms when expressed using the greedy algorithm as a sum of squares, 167 = 144 + 16 + 4 + 1 + 1 + 1, although by Lagrange's four-square theorem its non-greedy expression as a sum of squares can be shorter, e.g. 167 = 121 + 36 + 9 + 1.
167 is a full reptend prime in base 10, since the decimal expansion of 1/167 repeats the following 166 digits: 0.00598802395209580838323353293413173652694610778443113772455089820359281437125748502994 0119760479041916167664670658682634730538922155688622754491017964071856287425149700...
167 is a highly cototient number, as it is the smallest number k with exactly 15 solutions to the equation x - φ(x) = k. It is also a strictly non-palindromic number.
167 is the smallest multi-digit prime such that the product of digits is equal to the number of digits times the sum of the digits, i. e., 1×6×7 = 3×(1+6+7)
167 is the smallest positive integer d such that the imaginary quadratic field Q() has class number = 11.
References
References
- {{Cite OEIS. A109611. Chen primes: primes p such that p + 2 is either a prime or a semiprime
- {{Cite OEIS. A005385. Safe primes
- {{Cite OEIS. A006892
- "Tables of imaginary quadratic fields with small class number".
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