191911 has 2 divisors, whose sum is σ = 191912. Its totient is φ = 191910.

The previous prime is 191903. The next prime is 191929. The reversal of 191911 is 119191.

It is a weak prime.

It is an emirp because it is prime and its reverse (119191) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 191911 - 2³ = 191903 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (194911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95955 + 95956.

It is an arithmetic number, because the mean of its divisors is an integer number (95956).

2¹⁹¹⁹¹¹ is an apocalyptic number.

191911 is a deficient number, since it is larger than the sum of its proper divisors (1).

191911 is an equidigital number, since it uses as much as digits as its factorization.

191911 is an evil number, because the sum of its binary digits is even.

The product of its digits is 81, while the sum is 22.

The square root of 191911 is about 438.0764773416. The cubic root of 191911 is about 57.6810675310.

The spelling of 191911 in words is "one hundred ninety-one thousand, nine hundred eleven".