1221121210189 has 2 divisors, whose sum is σ = 1221121210190. Its totient is φ = 1221121210188.

The previous prime is 1221121210151. The next prime is 1221121210217. The reversal of 1221121210189 is 9810121211221.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1167890876100 + 53230334089 = 1080690^2 + 230717^2 .

It is an emirp because it is prime and its reverse (9810121211221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1221121210189 - 2⁹ = 1221121209677 is a prime.

It is a super-2 number, since 2×1221121210189² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1221121210189.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221121210789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610560605094 + 610560605095.

It is an arithmetic number, because the mean of its divisors is an integer number (610560605095).

Almost surely, 2^{1221121210189} is an apocalyptic number.

It is an amenable number.

1221121210189 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221121210189 is an equidigital number, since it uses as much as digits as its factorization.

1221121210189 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 31.

The spelling of 1221121210189 in words is "one trillion, two hundred twenty-one billion, one hundred twenty-one million, two hundred ten thousand, one hundred eighty-nine".