It is composite.
Number of Prime Numbers from 1 to 100 is 25. From 1 to 50 it was 15 From 50 to 100 it was 10
100 is composite. 100 = 2 * 2 * 5 * 5 = 22 * 52
100 is composite, because it has more than 2 factors.
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97