1213111213121 has 2 divisors, whose sum is σ = 1213111213122. Its totient is φ = 1213111213120.

The previous prime is 1213111213117. The next prime is 1213111213151. The reversal of 1213111213121 is 1213121113121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1203617439025 + 9493774096 = 1097095^2 + 97436^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213111213121 - 2² = 1213111213117 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1213111213093 and 1213111213102.

It is not a weakly prime, because it can be changed into another prime (1213111213151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606555606560 + 606555606561.

It is an arithmetic number, because the mean of its divisors is an integer number (606555606561).

Almost surely, 2^{1213111213121} is an apocalyptic number.

It is an amenable number.

1213111213121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213111213121 is an equidigital number, since it uses as much as digits as its factorization.

1213111213121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72, while the sum is 20.

Adding to 1213111213121 its reverse (1213121113121), we get a palindrome (2426232326242).

The spelling of 1213111213121 in words is "one trillion, two hundred thirteen billion, one hundred eleven million, two hundred thirteen thousand, one hundred twenty-one".