91191591 has 6 divisors (see below), whose sum is σ = 131721200. Its totient is φ = 60794388.

The previous prime is 91191571. The next prime is 91191599. The reversal of 91191591 is 19519119.

It is not a de Polignac number, because 91191591 - 2⁵ = 91191559 is a prime.

It is a super-2 number, since 2×91191591² = 16631812538222562, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91191599) 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 5 ways as a sum of consecutive naturals, for example, 5066191 + ... + 5066208.

Almost surely, 2^91191591 is an apocalyptic number.

91191591 is a deficient number, since it is larger than the sum of its proper divisors (40529609).

91191591 is a wasteful number, since it uses less digits than its factorization.

91191591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10132405 (or 10132402 counting only the distinct ones).

The product of its digits is 3645, while the sum is 36.

The square root of 91191591 is about 9549.4288310872. The cubic root of 91191591 is about 450.1095881247.

The spelling of 91191591 in words is "ninety-one million, one hundred ninety-one thousand, five hundred ninety-one".