191009191 has 8 divisors (see below), whose sum is σ = 194834160. Its totient is φ = 187259176.

The previous prime is 191009171. The next prime is 191009233. The reversal of 191009191 is 191900191.

191009191 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 191009191 - 2⁹ = 191008679 is a prime.

It is a super-2 number, since 2×191009191² = 72969022092948962, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191009131) 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, 148236 + ... + 149518.

It is an arithmetic number, because the mean of its divisors is an integer number (24354270).

Almost surely, 2^191009191 is an apocalyptic number.

191009191 is a deficient number, since it is larger than the sum of its proper divisors (3824969).

191009191 is an frugal number, since it uses more digits than its factorization.

191009191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1442 (or 1336 counting only the distinct ones).

The product of its (nonzero) digits is 729, while the sum is 31.

The square root of 191009191 is about 13820.6074757950. The cubic root of 191009191 is about 575.9057593617.

The spelling of 191009191 in words is "one hundred ninety-one million, nine thousand, one hundred ninety-one".