Across: A: Has the same digit sum as Q down.
D: A prime number.
F: A palindrome.
H: The digit sum of O down multiplied with M across and the square of A down.
K: All digits of K across are the same.
M: The addition of the digit sum of U across with the digit sum of N across.
N: P across multiple.
P: P across is both a cubic number and a square number.
R: A multiple of the digit sum of C down.
S: The subtraction of P down from Q down.
T: A palindrome.
U: P across divided by the digit sum of D across.

Down: A: A Mersenne Prime.
B: The subtraction of R down and D across from F across.
C: H across is a multiple of C down.
E: The multiplication of the first digit of F across with T down.
F: The reverse of Q down.
G: A palindrome.
I: Has the same digit sum as M down.
J: G down multiplied with E down, then subtract C down.
L: A palindrome.
M: A product of two prime numbers.
O: A quartic number.
P: A prime number.
Q: The multiplication of the first digit of S across multiplied by a prime number.
R: The addition of R across with the digit sum of R down.
T: A square number.