Across: A: A quartic number. C: A across plus A down. E: A prime number. G: A across multiply A down. I: J across divided by the digit sum of A down. J: G across multiplied by E across and the cube root of C across. M: Reverse of L down. N: A palindrome. P: A palindrome. R: A multiple of Z across. S: A palindrome. U: U down multiplied by Y across muliplied by the digit sum of O down. V: Has the same digit sum as W down. X: A prime number. Y: A prime number. Z: A non-prime number.
Down: A: A prime number. B: A palindrome. D: Has the same digit sum as G across. E: A palindrome. F: A quintic. H: Subtract M across from J across. K: A prime number. L: Has the same digit sum as X across. N: O down multiplied by V across. O: A non-prime number. Q: A prime number. R: A multiple of the reverse of F down. S: A square number. T: A palindrome. U: X across multiplied by the digit sum of Q down. W: Z across multiplied by the digit sum of O down.