2

This number is a prime.

Just showing those entries submitted by 'Firoozbakht': (Click here to show all)

The only prime p such that p times reversal(p) - 1 is prime. [Firoozbakht]

The only known number n such that the sum of the proper divisors of n is equal to phi(n). [Firoozbakht]

Only prime whose sum of divisors is prime. [Firoozbakht]