91090191 has 4 divisors (see below), whose sum is σ = 121453592. Its totient is φ = 60726792.

The previous prime is 91090171. The next prime is 91090201. The reversal of 91090191 is 19109019.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 91090191 - 2⁶ = 91090127 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 (91090171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15181696 + ... + 15181701.

It is an arithmetic number, because the mean of its divisors is an integer number (30363398).

Almost surely, 2^91090191 is an apocalyptic number.

91090191 is a deficient number, since it is larger than the sum of its proper divisors (30363401).

91090191 is a wasteful number, since it uses less digits than its factorization.

91090191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30363400.

The product of its (nonzero) digits is 729, while the sum is 30.

The square root of 91090191 is about 9544.1181363183. The cubic root of 91090191 is about 449.9426939371.

The spelling of 91090191 in words is "ninety-one million, ninety thousand, one hundred ninety-one".