13131...32131 (41-digits)

This number is a prime.

1 3131213111 3101391381 3713613513 4133132131

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f(13, 13) is a prime number, where f is the Firoozbakht function. Its sum of digits equals the prime 103. [Gudipati]

Submitted: 2026-06-23 02:03:03; Last Modified: 2026-06-23 06:08:25.