31231131332321 has 2 divisors, whose sum is σ = 31231131332322. Its totient is φ = 31231131332320.

The previous prime is 31231131332309. The next prime is 31231131332353. The reversal of 31231131332321 is 12323313113213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28196790304225 + 3034341028096 = 5310065^2 + 1741936^2 .

It is an emirp because it is prime and its reverse (12323313113213) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31231131332321 is a prime.

It is not a weakly prime, because it can be changed into another prime (31231131332371) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15615565666160 + 15615565666161.

It is an arithmetic number, because the mean of its divisors is an integer number (15615565666161).

Almost surely, 2^{31231131332321} is an apocalyptic number.

It is an amenable number.

31231131332321 is a deficient number, since it is larger than the sum of its proper divisors (1).

31231131332321 is an equidigital number, since it uses as much as digits as its factorization.

31231131332321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5832, while the sum is 29.

Adding to 31231131332321 its reverse (12323313113213), we get a palindrome (43554444445534).

The spelling of 31231131332321 in words is "thirty-one trillion, two hundred thirty-one billion, one hundred thirty-one million, three hundred thirty-two thousand, three hundred twenty-one".