1231310111021 has 2 divisors, whose sum is σ = 1231310111022. Its totient is φ = 1231310111020.

The previous prime is 1231310111011. The next prime is 1231310111029. The reversal of 1231310111021 is 1201110131321.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 761727472900 + 469582638121 = 872770^2 + 685261^2 .

It is an emirp because it is prime and its reverse (1201110131321) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1231310111021 is a prime.

It is a super-2 number, since 2×1231310111021² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1231310111029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615655055510 + 615655055511.

It is an arithmetic number, because the mean of its divisors is an integer number (615655055511).

Almost surely, 2^{1231310111021} is an apocalyptic number.

It is an amenable number.

1231310111021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231310111021 is an equidigital number, since it uses as much as digits as its factorization.

1231310111021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36, while the sum is 17.

Adding to 1231310111021 its reverse (1201110131321), we get a palindrome (2432420242342).

The spelling of 1231310111021 in words is "one trillion, two hundred thirty-one billion, three hundred ten million, one hundred eleven thousand, twenty-one".