191291 has 4 divisors (see below), whose sum is σ = 199632. Its totient is φ = 182952.

The previous prime is 191281. The next prime is 191297. The reversal of 191291 is 192191.

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

It is a cyclic number.

It is not a de Polignac number, because 191291 - 2⁶ = 191227 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23), and also a Moran number because the ratio is a prime number: 8317 = 191291 / (1 + 9 + 1 + 2 + 9 + 1).

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 191291.

It is not an unprimeable number, because it can be changed into a prime (191297) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4136 + ... + 4181.

It is an arithmetic number, because the mean of its divisors is an integer number (49908).

2¹⁹¹²⁹¹ is an apocalyptic number.

191291 is a deficient number, since it is larger than the sum of its proper divisors (8341).

191291 is an equidigital number, since it uses as much as digits as its factorization.

191291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8340.

The product of its digits is 162, while the sum is 23.

The square root of 191291 is about 437.3682658813. The cubic root of 191291 is about 57.6188844651.

Subtracting 191291 from its reverse (192191), we obtain a square (900 = 30²).

The spelling of 191291 in words is "one hundred ninety-one thousand, two hundred ninety-one".