The answer is:
Rational
Work/explanation:
23² = 529
529 is a whole number.
All whole numbers are rational.
What are rational numbers?
These are numbers that can be expressed in the form of p/q, where q ≠ 0.
Can 529 be expressed in p/q form? Well, we can try.
529 = 529/1, which is p/q form.
Hence, 529 is rational.