1313021111981 has 2 divisors, whose sum is σ = 1313021111982. Its totient is φ = 1313021111980.

The previous prime is 1313021111957. The next prime is 1313021112041. The reversal of 1313021111981 is 1891111203131.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 758003561956 + 555017550025 = 870634^2 + 744995^2 .

It is a cyclic number.

It is not a de Polignac number, because 1313021111981 - 2⁶ = 1313021111917 is a prime.

It is a super-2 number, since 2×1313021111981² (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 (1313021111911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 656510555990 + 656510555991.

It is an arithmetic number, because the mean of its divisors is an integer number (656510555991).

Almost surely, 2^{1313021111981} is an apocalyptic number.

It is an amenable number.

1313021111981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1313021111981 is an equidigital number, since it uses as much as digits as its factorization.

1313021111981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1296, while the sum is 32.

The spelling of 1313021111981 in words is "one trillion, three hundred thirteen billion, twenty-one million, one hundred eleven thousand, nine hundred eighty-one".