1221120210181 has 2 divisors, whose sum is σ = 1221120210182. Its totient is φ = 1221120210180.

The previous prime is 1221120210169. The next prime is 1221120210221. The reversal of 1221120210181 is 1810120211221.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 621943585956 + 599176624225 = 788634^2 + 774065^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221120210181 - 2¹⁵ = 1221120177413 is a prime.

It is a super-2 number, since 2×1221120210181² (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 (1221120210131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610560105090 + 610560105091.

It is an arithmetic number, because the mean of its divisors is an integer number (610560105091).

Almost surely, 2^{1221120210181} is an apocalyptic number.

It is an amenable number.

1221120210181 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221120210181 is an equidigital number, since it uses as much as digits as its factorization.

1221120210181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 22.

The spelling of 1221120210181 in words is "one trillion, two hundred twenty-one billion, one hundred twenty million, two hundred ten thousand, one hundred eighty-one".