1211123191 has 2 divisors, whose sum is σ = 1211123192. Its totient is φ = 1211123190.

The previous prime is 1211123189. The next prime is 1211123203. The reversal of 1211123191 is 1913211121.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1211123191 - 2¹ = 1211123189 is a prime.

Together with 1211123189, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211123791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605561595 + 605561596.

It is an arithmetic number, because the mean of its divisors is an integer number (605561596).

Almost surely, 2^1211123191 is an apocalyptic number.

1211123191 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211123191 is an equidigital number, since it uses as much as digits as its factorization.

1211123191 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108, while the sum is 22.

The square root of 1211123191 is about 34801.1952524622. The cubic root of 1211123191 is about 1065.9318523856.

The spelling of 1211123191 in words is "one billion, two hundred eleven million, one hundred twenty-three thousand, one hundred ninety-one".