206115191 has 4 divisors (see below), whose sum is σ = 218239632. Its totient is φ = 193990752.

The previous prime is 206115181. The next prime is 206115193. The reversal of 206115191 is 191511602.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-206115191 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 206115191.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (206115193) 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 in 3 ways as a sum of consecutive naturals, for example, 6062195 + ... + 6062228.

It is an arithmetic number, because the mean of its divisors is an integer number (54559908).

Almost surely, 2^206115191 is an apocalyptic number.

206115191 is a deficient number, since it is larger than the sum of its proper divisors (12124441).

206115191 is a wasteful number, since it uses less digits than its factorization.

206115191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12124440.

The product of its (nonzero) digits is 540, while the sum is 26.

The square root of 206115191 is about 14356.7124022180. The cubic root of 206115191 is about 590.7041205689.

Adding to 206115191 its reverse (191511602), we get a palindrome (397626793).

The spelling of 206115191 in words is "two hundred six million, one hundred fifteen thousand, one hundred ninety-one".