Prime Curios!: 80

80
(another Prime Pages' Curiosity)

Curios:

Curios Search: Participate:

There are 80 four-digit primes which are concatenations of two-digit primes. [De Geest]

(10⁸⁰ - 80)/80 is prime. [Luhn]

80^(80+1) + (80+1)^80 is prime.

The only two-digit integer n that yields a prime in the form n^(n+1)+(n+1)^n. [Silva]

The smallest integer n such that both n and n+1 are products of at least 4 primes. [Post]