191145891 has 4 divisors (see below), whose sum is σ = 254861192. Its totient is φ = 127430592.

The previous prime is 191145883. The next prime is 191145937. The reversal of 191145891 is 198541191.

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

It is not a de Polignac number, because 191145891 - 2³ = 191145883 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (191145881) 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, 31857646 + ... + 31857651.

It is an arithmetic number, because the mean of its divisors is an integer number (63715298).

Almost surely, 2^191145891 is an apocalyptic number.

191145891 is a deficient number, since it is larger than the sum of its proper divisors (63715301).

191145891 is an equidigital number, since it uses as much as digits as its factorization.

191145891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63715300.

The product of its digits is 12960, while the sum is 39.

The square root of 191145891 is about 13825.5521047082. The cubic root of 191145891 is about 576.0431132129.

The spelling of 191145891 in words is "one hundred ninety-one million, one hundred forty-five thousand, eight hundred ninety-one".