1221121211021 has 2 divisors, whose sum is σ = 1221121211022. Its totient is φ = 1221121211020.

The previous prime is 1221121210993. The next prime is 1221121211029. The reversal of 1221121211021 is 1201121211221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1203222517225 + 17898693796 = 1096915^2 + 133786^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221121211021 - 2⁶ = 1221121210957 is a prime.

It is a super-2 number, since 2×1221121211021² (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 (1221121211029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610560605510 + 610560605511.

It is an arithmetic number, because the mean of its divisors is an integer number (610560605511).

Almost surely, 2^{1221121211021} is an apocalyptic number.

It is an amenable number.

1221121211021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221121211021 is an equidigital number, since it uses as much as digits as its factorization.

1221121211021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 1221121211021 its reverse (1201121211221), we get a palindrome (2422242422242).

The spelling of 1221121211021 in words is "one trillion, two hundred twenty-one billion, one hundred twenty-one million, two hundred eleven thousand, twenty-one".