9811220191 has 2 divisors, whose sum is σ = 9811220192. Its totient is φ = 9811220190.

The previous prime is 9811220189. The next prime is 9811220203. The reversal of 9811220191 is 1910221189.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 9811220191 - 2¹ = 9811220189 is a prime.

Together with 9811220189, 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 (9811220291) 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, 4905610095 + 4905610096.

It is an arithmetic number, because the mean of its divisors is an integer number (4905610096).

Almost surely, 2^9811220191 is an apocalyptic number.

9811220191 is a deficient number, since it is larger than the sum of its proper divisors (1).

9811220191 is an equidigital number, since it uses as much as digits as its factorization.

9811220191 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 34.

The square root of 9811220191 is about 99051.6036770733. The cubic root of 9811220191 is about 2140.7913478687.

The spelling of 9811220191 in words is "nine billion, eight hundred eleven million, two hundred twenty thousand, one hundred ninety-one".