No zeros occur in this puzzle.
A: N across + E across.
E: a cubic number.
F: the reverse of F across is a prime number.
H: I across + K down.
I: subtract D down from I across, and the result is a square number.
J: a prime number.
L: all digits of L across are the same.
N: subtract L across from A across and read the result backwards, and you get N across.
A: D down multiplied with E across.
B: a square number.
C: another square number.
D: a prime number.
G: D down multiplied with the reverse of I across.
K: I across - D down.
L: a palindrome.
M: a prime number.