1221121111213 has 2 divisors, whose sum is σ = 1221121111214. Its totient is φ = 1221121111212.

The previous prime is 1221121111193. The next prime is 1221121111219. The reversal of 1221121111213 is 3121111211221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1220101394724 + 1019716489 = 1104582^2 + 31933^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221121111213 is a prime.

It is a super-2 number, since 2×1221121111213² (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 (1221121111219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610560555606 + 610560555607.

It is an arithmetic number, because the mean of its divisors is an integer number (610560555607).

Almost surely, 2^{1221121111213} is an apocalyptic number.

It is an amenable number.

1221121111213 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221121111213 is an equidigital number, since it uses as much as digits as its factorization.

1221121111213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48, while the sum is 19.

Adding to 1221121111213 its reverse (3121111211221), we get a palindrome (4342232322434).

The spelling of 1221121111213 in words is "one trillion, two hundred twenty-one billion, one hundred twenty-one million, one hundred eleven thousand, two hundred thirteen".