1211123189 has 2 divisors, whose sum is σ = 1211123190. Its totient is φ = 1211123188.

The previous prime is 1211123077. The next prime is 1211123191. The reversal of 1211123189 is 9813211121.

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., 1132659025 + 78464164 = 33655^2 + 8858^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1211123189 is a prime.

Together with 1211123191, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211129189) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605561594 + 605561595.

It is an arithmetic number, because the mean of its divisors is an integer number (605561595).

Almost surely, 2^1211123189 is an apocalyptic number.

It is an amenable number.

1211123189 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211123189 is an equidigital number, since it uses as much as digits as its factorization.

1211123189 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 864, while the sum is 29.

The square root of 1211123189 is about 34801.1952237276. The cubic root of 1211123189 is about 1065.9318517989.

The spelling of 1211123189 in words is "one billion, two hundred eleven million, one hundred twenty-three thousand, one hundred eighty-nine".