Prime Curios!: 49

49
(another Prime Pages' Curiosity)

Curios:

Curios Search: Participate:

The smallest composite number whose digits are composite such that the concatenated factors of either digit with the remaining digit(s) is prime. [Rivera]

The first 49 digits after the decimal point in e = 2.718... form a prime. [Honaker]

The largest prime square which is greater than the product of all lesser primes. [Murthy]

49 is the smallest number which is the concatenation of two prime squares creating another prime square. [Sladcik]

The smallest semiprime whose sum of divisors is also a semiprime. [Gupta]

phi(49)*49^49 + 1 is prime. The reversal of 49 has the same property. [Firoozbakht]

The smallest square that is the sum of three consecutive primes. [Silva]