1221101222021 has 2 divisors, whose sum is σ = 1221101222022. Its totient is φ = 1221101222020.

The previous prime is 1221101221987. The next prime is 1221101222023. The reversal of 1221101222021 is 1202221011221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 701816685025 + 519284536996 = 837745^2 + 720614^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221101222021 is a prime.

It is a Sophie Germain prime.

Together with 1221101222023, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221101222023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610550611010 + 610550611011.

It is an arithmetic number, because the mean of its divisors is an integer number (610550611011).

Almost surely, 2^{1221101222021} is an apocalyptic number.

It is an amenable number.

1221101222021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221101222021 is an equidigital number, since it uses as much as digits as its factorization.

1221101222021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 1221101222021 its reverse (1202221011221), we get a palindrome (2423322233242).

The spelling of 1221101222021 in words is "one trillion, two hundred twenty-one billion, one hundred one million, two hundred twenty-two thousand, twenty-one".