1221222201961 has 2 divisors, whose sum is σ = 1221222201962. Its totient is φ = 1221222201960.

The previous prime is 1221222201931. The next prime is 1221222202021. The reversal of 1221222201961 is 1691022221221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 932228870400 + 288993331561 = 965520^2 + 537581^2 .

It is an emirp because it is prime and its reverse (1691022221221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1221222201961 - 2⁵ = 1221222201929 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221222201911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610611100980 + 610611100981.

It is an arithmetic number, because the mean of its divisors is an integer number (610611100981).

Almost surely, 2^{1221222201961} is an apocalyptic number.

It is an amenable number.

1221222201961 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221222201961 is an equidigital number, since it uses as much as digits as its factorization.

1221222201961 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 31.

The spelling of 1221222201961 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-two million, two hundred one thousand, nine hundred sixty-one".