10991191 has 6 divisors (see below), whose sum is σ = 11160240. Its totient is φ = 10822968.

The previous prime is 10991173. The next prime is 10991207. The reversal of 10991191 is 19119901.

It is not a de Polignac number, because 10991191 - 2⁵ = 10991159 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10991111) 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, 29281 + ... + 29653.

It is an arithmetic number, because the mean of its divisors is an integer number (1860040).

Almost surely, 2^10991191 is an apocalyptic number.

10991191 is a deficient number, since it is larger than the sum of its proper divisors (169049).

10991191 is an frugal number, since it uses more digits than its factorization.

10991191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 825 (or 452 counting only the distinct ones).

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

The square root of 10991191 is about 3315.2965176587. The cubic root of 10991191 is about 222.3386264128.

The spelling of 10991191 in words is "ten million, nine hundred ninety-one thousand, one hundred ninety-one".