91087191 has 12 divisors (see below), whose sum is σ = 141691368. Its totient is φ = 56053584.

The previous prime is 91087189. The next prime is 91087211. The reversal of 91087191 is 19178019.

It is not a de Polignac number, because 91087191 - 2¹ = 91087189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91087111) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 389145 + ... + 389378.

It is an arithmetic number, because the mean of its divisors is an integer number (11807614).

Almost surely, 2^91087191 is an apocalyptic number.

91087191 is a deficient number, since it is larger than the sum of its proper divisors (50604177).

91087191 is a wasteful number, since it uses less digits than its factorization.

91087191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 778542 (or 778539 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 36.

The square root of 91087191 is about 9543.9609701633. The cubic root of 91087191 is about 449.9377543533.

The spelling of 91087191 in words is "ninety-one million, eighty-seven thousand, one hundred ninety-one".