206321191 has 2 divisors, whose sum is σ = 206321192. Its totient is φ = 206321190.

The previous prime is 206321189. The next prime is 206321239. The reversal of 206321191 is 191123602.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 206321191 - 2¹ = 206321189 is a prime.

Together with 206321189, 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 (206325191) 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, 103160595 + 103160596.

It is an arithmetic number, because the mean of its divisors is an integer number (103160596).

Almost surely, 2^206321191 is an apocalyptic number.

206321191 is a deficient number, since it is larger than the sum of its proper divisors (1).

206321191 is an equidigital number, since it uses as much as digits as its factorization.

206321191 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 206321191 is about 14363.8849549835. The cubic root of 206321191 is about 590.9008463766.

Adding to 206321191 its reverse (191123602), we get a palindrome (397444793).

The spelling of 206321191 in words is "two hundred six million, three hundred twenty-one thousand, one hundred ninety-one".