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Question 2 · Sep 29 · Day 20

Gemini on Question 2, Sep 29

Is 9973 a prime number? Think step by step and then answer "[Yes]" or "[No]".

To determine if 9973 is a prime number, we can check if it is divisible by any prime numbers up to its square root.

  • 1.The square root of 9973 is approximately 99.86. So, we need to test prime numbers up to 99:

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, and 97.

  • 2.Let's do some quick checks for the smallest primes:
  • •2: 9973 is not even.
  • •3: The sum of the digits (9 + 9 + 7 + 3 = 28) is not divisible by 3.
  • •5: It does not end in 0 or 5.
  • •7: 9973 / 7 = 1424 with a remainder of 5.
  • •11: The alternating sum of digits (3 - 7 + 9 - 9 = -4) is not a multiple of 11.
  • 3.We can continue this division for the rest of the primes up to 97:
  • •9973 / 13 = 767 remainder 2
  • •9973 / 17 = 586 remainder 11
  • •9973 / 19 = 524 remainder 17
  • •...
  • •9973 / 89 = 112 remainder 5
  • •9973 / 97 = 102 remainder 79

Since 9973 cannot be evenly divided by any prime number up to its square root, it has no divisors other than 1 and itself. (In fact, 9973 is well-known in mathematics for being the largest four-digit prime number).

[Yes]

sha256 57b3463110bd… · 24 tokens in · 2,715 out · 18.0 s · via Google · stopped on its own

Sep 29, the whole dayQuestion 2, every day

Exact recordShowHideThe model id, the run, the verbatim text with line numbers and its full sha256
Model
google/gemini-3.1-pro-preview
pinned google/gemini-3.1-pro-preview-20260219; alias resolved to google/gemini-3.1-pro-preview-20260219 at 2026-09-29 09:00:07 UTC (matches the pin)
Date
2026-09-29 · run 20260929T090007Z-334891 · scorer v1
Scored
answered · correct · format ok
Changes
Minor Length anomaly: gave a shorter answer than usual to the question whether 9973 is prime, about 60% of its usual length
sha256
57b3463110bd01e340cedfa506e4e303adb592604b176b1f757e707533c8fa3c
Permalink
https://modeldrift.watch/r/2026-09-29/D2/google/gemini-3.1-pro-preview/
Scored
answered · correct · format ok
Received
2026-09-29 09:00:56 UTC
Run
20260929T090007Z-334891
Served by
Google · HTTP 200 · finish stop
Size
1,094 characters · 2,715 tokens out incl. hidden reasoning · 18.0 s

Highlighted: the last [Yes]/[No] bracket, which is the scored answer (Yes).

To determine if 9973 is a prime number, we can check if it is divisible by any prime numbers up to its square root.
1. The square root of 9973 is approximately 99.86. So, we need to test prime numbers up to 99:
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, and 97.
2. Let's do some quick checks for the smallest primes:
- **2**: 9973 is not even.
- **3**: The sum of the digits (9 + 9 + 7 + 3 = 28) is not divisible by 3.
- **5**: It does not end in 0 or 5.
- **7**: 9973 / 7 = 1424 with a remainder of 5.
- **11**: The alternating sum of digits (3 - 7 + 9 - 9 = -4) is not a multiple of 11.
3. We can continue this division for the rest of the primes up to 97:
- 9973 / 13 = 767 remainder 2
- 9973 / 17 = 586 remainder 11
- 9973 / 19 = 524 remainder 17
- ...
- 9973 / 89 = 112 remainder 5
- 9973 / 97 = 102 remainder 79
Since 9973 cannot be evenly divided by any prime number up to its square root, it has no divisors other than 1 and itself. (In fact, 9973 is well-known in mathematics for being the largest four-digit prime number).
[Yes]

End of response · 23 lines · 1,094 characters · sha256 57b3463110bd01e340cedfa506e4e303adb592604b176b1f757e707533c8fa3c