This code is a simple substitution code. A number is substituted for a letter. In this code if you counted off the letters with a=1 until you reached z=26, you would have broken the code.
1
2
3
4
5
6
7
8
9
10
11
12
13
A
B
C
D
E
F
G
H
I
J
K
L
M
14
15
16
17
18
19
20
21
22
23
24
25
26
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
The message Is:
Angels and Demons both visit Earth, be careful who you hang out with.