31231311221113 has 2 divisors, whose sum is σ = 31231311221114. Its totient is φ = 31231311221112.

The previous prime is 31231311221093. The next prime is 31231311221137. The reversal of 31231311221113 is 31112211313213.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 22919553028969 + 8311758192144 = 4787437^2 + 2883012^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31231311221113 is a prime.

It is not a weakly prime, because it can be changed into another prime (31231311221153) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15615655610556 + 15615655610557.

It is an arithmetic number, because the mean of its divisors is an integer number (15615655610557).

Almost surely, 2^{31231311221113} is an apocalyptic number.

It is an amenable number.

31231311221113 is a deficient number, since it is larger than the sum of its proper divisors (1).

31231311221113 is an equidigital number, since it uses as much as digits as its factorization.

31231311221113 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 25.

Adding to 31231311221113 its reverse (31112211313213), we get a palindrome (62343522534326).

The spelling of 31231311221113 in words is "thirty-one trillion, two hundred thirty-one billion, three hundred eleven million, two hundred twenty-one thousand, one hundred thirteen".