All one- and two-digit numbers that look prime are prime, except 91.

This assumes that you can easily identify - multiples of 2 and 5 (by their last digit) - multiples of 3 (the sum of their digits is divisible by 3) - multiples of 11 (for two-digit ones, they have both digits the same: 11, 22, 33, ..., 99) - squares

So the first number that looks prime but isn't is the product of the two smallest primes that aren't "easy", which is 7*13 = 91.