1211222191 has 2 divisors, whose sum is σ = 1211222192. Its totient is φ = 1211222190.

The previous prime is 1211222183. The next prime is 1211222213. The reversal of 1211222191 is 1912221121.

It is an a-pointer prime, because the next prime (1211222213) can be obtained adding 1211222191 to its sum of digits (22).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1211222191 - 2³ = 1211222183 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1211222291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605611095 + 605611096.

It is an arithmetic number, because the mean of its divisors is an integer number (605611096).

Almost surely, 2^1211222191 is an apocalyptic number.

1211222191 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211222191 is an equidigital number, since it uses as much as digits as its factorization.

1211222191 is an evil number, because the sum of its binary digits is even.

The product of its digits is 144, while the sum is 22.

The square root of 1211222191 is about 34802.6175883367. The cubic root of 1211222191 is about 1065.9608955028.

The spelling of 1211222191 in words is "one billion, two hundred eleven million, two hundred twenty-two thousand, one hundred ninety-one".