121220111221813 has 2 divisors, whose sum is σ = 121220111221814. Its totient is φ = 121220111221812.

The previous prime is 121220111221709. The next prime is 121220111221823. The reversal of 121220111221813 is 318122111022121.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 110816086794084 + 10404024427729 = 10526922^2 + 3225527^2 .

It is a cyclic number.

It is not a de Polignac number, because 121220111221813 - 2²¹ = 121220109124661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (121220111221823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60610055610906 + 60610055610907.

It is an arithmetic number, because the mean of its divisors is an integer number (60610055610907).

Almost surely, 2^{121220111221813} is an apocalyptic number.

It is an amenable number.

121220111221813 is a deficient number, since it is larger than the sum of its proper divisors (1).

121220111221813 is an equidigital number, since it uses as much as digits as its factorization.

121220111221813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 768, while the sum is 28.

Adding to 121220111221813 its reverse (318122111022121), we get a palindrome (439342222243934).

The spelling of 121220111221813 in words is "one hundred twenty-one trillion, two hundred twenty billion, one hundred eleven million, two hundred twenty-one thousand, eight hundred thirteen".