Owlet puzzle #29
Released Monday, August 3, 2026 UTC
1000000007
the answer for puzzle #29
The five clues
- A ten-digit prime.
- A prime just past a landmark round number.
- The smallest prime greater than 10⁹; used widely as a modulus in competitive programming.
- It equals 10⁹ + 7, seven greater than a billion (not one).
- So common in Codeforces problems that many templates simply hardcode 'const int MOD = 1e9 + 7'.
Backstory
10⁹ + 7 is a prime frequently chosen as the default modulus in competitive programming: large enough to reduce collisions in integer hashing, small enough that products fit in 64-bit integers. It's also a safe prime — (10⁹+7 − 1)/2 = 500000003 is prime.
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