191091243 has 8 divisors (see below), whose sum is σ = 291186688. Its totient is φ = 109194984.

The previous prime is 191091239. The next prime is 191091259. The reversal of 191091243 is 342190191.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 191091243 - 2² = 191091239 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 191091243.

It is not an unprimeable number, because it can be changed into a prime (191091343) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4549771 + ... + 4549812.

It is an arithmetic number, because the mean of its divisors is an integer number (36398336).

Almost surely, 2^191091243 is an apocalyptic number.

191091243 is a deficient number, since it is larger than the sum of its proper divisors (100095445).

191091243 is an equidigital number, since it uses as much as digits as its factorization.

191091243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9099593.

The product of its (nonzero) digits is 1944, while the sum is 30.

The square root of 191091243 is about 13823.5756228264. The cubic root of 191091243 is about 575.9882116849.

The spelling of 191091243 in words is "one hundred ninety-one million, ninety-one thousand, two hundred forty-three".