MathCastle
Number TheorySuperchallengeDigits and Bases

Digits and Bases · Superchallenge problem

Find the smallest base b≥2b \ge 2 for which the base-bb numeral 1001b1001_b is a multiple of 20262026. (Note 2026=2⋅10132026 = 2 \cdot 1013, and 10131013 is prime.)