191019091 has 6 divisors (see below), whose sum is σ = 192505676. Its totient is φ = 189543900.

The previous prime is 191019061. The next prime is 191019097. The reversal of 191019091 is 190910191.

191019091 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 191019091 - 2¹³ = 191010899 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (191019097) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 11596 + ... + 22726.

Almost surely, 2^191019091 is an apocalyptic number.

191019091 is a deficient number, since it is larger than the sum of its proper divisors (1486585).

191019091 is an equidigital number, since it uses as much as digits as its factorization.

191019091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11393 (or 11262 counting only the distinct ones).

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

The square root of 191019091 is about 13820.9656319665. The cubic root of 191019091 is about 575.9157089152.

Subtracting from 191019091 its reverse (190910191), we obtain a square (108900 = 330²).

The spelling of 191019091 in words is "one hundred ninety-one million, nineteen thousand, ninety-one".