No zeros occur in this puzzle.

**Across**:

**A**: a palindrome.

**C**: a palindrome.

**E**: divide this palindrome by C across, and the result equals four times the digit product of P down.

**G**: 4 times N down.

**J**: a prime number.

**L**: J down + K down.

**M**: the third power of A down.

**N**: if this palindrome is divided by A across, the result is another palindrome.

**P**: P across divided by T across equals the digit sum of P across.

**Q**: a prime number.

**S**: S across divided by O down is a prime number.

**T**: a prime number.

**U**: this prime number is a divisor of J down.

**Down**:

**A**: a cubic number.

**B**: C down minus the reverse of G across.

**C**: a prime number.

**D**: the reverse of the prime number D down divided by the digit sum of C across is a square number.

**F**: the third power of A across.

**H**: H down divided by D down equals N across divided by A across.

**I**: I across divided by Q across equals half the digit product of P down.

**J**: a palindrome.

**K**: K down divided by J across equals the digit sum of J down.

**N**: a prime number.

**O**: a prime number.

**P**: the digit product of A across multiplied with the digit product of N across.

**R**: this palindrome equals C across plus T across.