1231221220013 has 2 divisors, whose sum is σ = 1231221220014. Its totient is φ = 1231221220012.

The previous prime is 1231221220003. The next prime is 1231221220043. The reversal of 1231221220013 is 3100221221321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1162284516649 + 68936703364 = 1078093^2 + 262558^2 .

It is a cyclic number.

It is not a de Polignac number, because 1231221220013 - 2²⁶ = 1231154111149 is a prime.

It is a super-2 number, since 2×1231221220013² (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 (1231221220003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615610610006 + 615610610007.

It is an arithmetic number, because the mean of its divisors is an integer number (615610610007).

Almost surely, 2^{1231221220013} is an apocalyptic number.

It is an amenable number.

1231221220013 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231221220013 is an equidigital number, since it uses as much as digits as its factorization.

1231221220013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 20.

Adding to 1231221220013 its reverse (3100221221321), we get a palindrome (4331442441334).

The spelling of 1231221220013 in words is "one trillion, two hundred thirty-one billion, two hundred twenty-one million, two hundred twenty thousand, thirteen".