199791816191 has 16 divisors (see below), whose sum is σ = 218856079008. Its totient is φ = 180878131200.

The previous prime is 199791816157. The next prime is 199791816233. The reversal of 199791816191 is 191618197991.

It is a happy number.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-199791816191 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199791816121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19108121 + ... + 19118573.

It is an arithmetic number, because the mean of its divisors is an integer number (13678504938).

Almost surely, 2^199791816191 is an apocalyptic number.

199791816191 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

199791816191 is a deficient number, since it is larger than the sum of its proper divisors (19064262817).

199791816191 is a wasteful number, since it uses less digits than its factorization.

199791816191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17482.

The product of its digits is 2204496, while the sum is 62.

The spelling of 199791816191 in words is "one hundred ninety-nine billion, seven hundred ninety-one million, eight hundred sixteen thousand, one hundred ninety-one".