1091009191 has 2 divisors, whose sum is σ = 1091009192. Its totient is φ = 1091009190.

The previous prime is 1091009189. The next prime is 1091009243. The reversal of 1091009191 is 1919001901.

It is a weak prime.

It is an emirp because it is prime and its reverse (1919001901) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1091009191 - 2¹ = 1091009189 is a prime.

Together with 1091009189, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1091003191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 545504595 + 545504596.

It is an arithmetic number, because the mean of its divisors is an integer number (545504596).

Almost surely, 2^1091009191 is an apocalyptic number.

1091009191 is a deficient number, since it is larger than the sum of its proper divisors (1).

1091009191 is an equidigital number, since it uses as much as digits as its factorization.

1091009191 is an odious number, because the sum of its binary digits is odd.

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

The square root of 1091009191 is about 33030.4282594095. The cubic root of 1091009191 is about 1029.4599836802.

The spelling of 1091009191 in words is "one billion, ninety-one million, nine thousand, one hundred ninety-one".