91511591 has 2 divisors, whose sum is σ = 91511592. Its totient is φ = 91511590.

The previous prime is 91511569. The next prime is 91511593. The reversal of 91511591 is 19511519.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 91511591 - 2¹⁰ = 91510567 is a prime.

Together with 91511593, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91511593) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45755795 + 45755796.

It is an arithmetic number, because the mean of its divisors is an integer number (45755796).

Almost surely, 2^91511591 is an apocalyptic number.

91511591 is a deficient number, since it is larger than the sum of its proper divisors (1).

91511591 is an equidigital number, since it uses as much as digits as its factorization.

91511591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2025, while the sum is 32.

The square root of 91511591 is about 9566.1690869438. The cubic root of 91511591 is about 450.6354659924.

The spelling of 91511591 in words is "ninety-one million, five hundred eleven thousand, five hundred ninety-one".