To factor the quadratic equation \( x^2 + 10x + 16 = 0 \), we need to find two numbers that multiply to \( 16 \) (the constant term) and add up to \( 10 \) (the coefficient of \( x \)).
The numbers that meet these criteria are \( 2 \) and \( 8 \), since:
- \( 2 + 8 = 10 \)
- \( 2 \times 8 = 16 \)
Thus, we can write the quadratic in its factored form as:
\[ (x + 2)(x + 8) = 0 \]
The lesser number is \( 2 \) and the other number is \( 8 \). Therefore, the answer is:
\[ 2, 8 \]