211198991 has 2 divisors, whose sum is σ = 211198992. Its totient is φ = 211198990.

The previous prime is 211198987. The next prime is 211199029. The reversal of 211198991 is 199891112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 211198991 - 2² = 211198987 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211198901) 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, 105599495 + 105599496.

It is an arithmetic number, because the mean of its divisors is an integer number (105599496).

Almost surely, 2^211198991 is an apocalyptic number.

211198991 is a deficient number, since it is larger than the sum of its proper divisors (1).

211198991 is an equidigital number, since it uses as much as digits as its factorization.

211198991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11664, while the sum is 41.

The square root of 211198991 is about 14532.6869848628. The cubic root of 211198991 is about 595.5212728184.

The spelling of 211198991 in words is "two hundred eleven million, one hundred ninety-eight thousand, nine hundred ninety-one".