19735
It's reasoned out by 3 steps:
1. as all the ppl achieved the same number of successful guesses, and denote N is the number of successful guesses, N = 1,2,3,4,5. As all Zhao's number were covered by successful guesses. 1 and 5 are discarded. Because none of the numbers guessed out by individuals is adjoined to each other. so 3 and 4 are discarded. N=2 .
2. observe the distribution of the 3 telephone number guessed by 3 ppl. 3 is repeated once. assume 3 is not correct, then 1 is correct, then, due to rules in 1, one of 9 and 3 guessed by wang should be correct. Then you will find you reach a deadlock which can not satisfy all the rules stated by Zhao. Therefore 3 is correct. Now we obtain the fourth number of Zhao's telephone: 3
3. If 3 is correct and no correct numbers are near to each other, 5 and 8 in Zhang's row and 2 and 9 in Li's row are wrong. Then the first two number should be either 7 5 or 1 9. After one or two steps of manipulation, you will find on 1 9 is possible to satisfy all the rules.
Then the last two unknown digit become obvious.