To compute \( 987654321 \) squared, we can use the formula for squaring a number:

\[
x^2 = x \times x
\]

where \( x = 987654321 \).

Calculating directly:

\[
987654321^2 = 975461057789971041
\]

Thus, the exact value of \( 987654321 \) squared is:

\[
\boxed{975461057789971041}
\]
