1331320321 has 2 divisors, whose sum is σ = 1331320322. Its totient is φ = 1331320320.

The previous prime is 1331320271. The next prime is 1331320343. The reversal of 1331320321 is 1230231331.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1266292225 + 65028096 = 35585^2 + 8064^2 .

It is a cyclic number.

It is not a de Polignac number, because 1331320321 - 2⁹ = 1331319809 is a prime.

It is not a weakly prime, because it can be changed into another prime (1331320021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 665660160 + 665660161.

It is an arithmetic number, because the mean of its divisors is an integer number (665660161).

Almost surely, 2^1331320321 is an apocalyptic number.

It is an amenable number.

1331320321 is a deficient number, since it is larger than the sum of its proper divisors (1).

1331320321 is an equidigital number, since it uses as much as digits as its factorization.

1331320321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324, while the sum is 19.

The square root of 1331320321 is about 36487.2624486957. The cubic root of 1331320321 is about 1100.0882356218.

Adding to 1331320321 its reverse (1230231331), we get a palindrome (2561551652).

The spelling of 1331320321 in words is "one billion, three hundred thirty-one million, three hundred twenty thousand, three hundred twenty-one".