91649191 has 2 divisors, whose sum is σ = 91649192. Its totient is φ = 91649190.

The previous prime is 91649171. The next prime is 91649197. The reversal of 91649191 is 19194619.

It is a strong prime.

It is an emirp because it is prime and its reverse (19194619) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91649191 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91649197) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45824595 + 45824596.

It is an arithmetic number, because the mean of its divisors is an integer number (45824596).

Almost surely, 2^91649191 is an apocalyptic number.

91649191 is a deficient number, since it is larger than the sum of its proper divisors (1).

91649191 is an equidigital number, since it uses as much as digits as its factorization.

91649191 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17496, while the sum is 40.

The square root of 91649191 is about 9573.3583971352. The cubic root of 91649191 is about 450.8612165833.

The spelling of 91649191 in words is "ninety-one million, six hundred forty-nine thousand, one hundred ninety-one".