We show that under Dickson's conjecture about the distribution of primes in the natural numbers, the theory T h (Z, +, 1, 0, P r) where P r is a predicate for the prime numbers and their negations is decidable, unstable and supersimple. This is in contrast with T h (Z, +, 0, P r, <) which is known to be undecidable by the works of Jockusch, Bateman and Woods.2010 Mathematics Subject Classification. 03C45, 03F30, 03B25, 11A41.