This number is a prime.

+ The smallest prime whose conversion from seconds into hours, minutes, and seconds, gives a prime number of hours, minutes, and seconds (7331s = 2h 2m 11s). [Thoms]

+ The larger of only two right-truncatable primes formed by concatenating two double-digit right-truncatable emirps. The other is 3137. [Loungrides]

+ The largest of only three right-truncatable primes, each formed by concatenating two double-digit emirps. The other two are 3137 and 3797. Note that 7331 is the only right-truncatable prime concatenated in descending order from two double-digit emirps. [Loungrides]

+ The only prime concatenated from two double-digit primes p, g whose first prime is the 73. [Loungrides]

+ 7331, 73331, 733331 and 7333331 are all prime numbers. [Anitha]

(There is one curio for this number that has not yet been approved by an editor.)

Printed from the PrimePages <t5k.org> © G. L. Honaker and Chris K. Caldwell