91643975 has 6 divisors (see below), whose sum is σ = 113638560. Its totient is φ = 73315160.

The previous prime is 91643971. The next prime is 91643977. The reversal of 91643975 is 57934619.

It is not a de Polignac number, because 91643975 - 2² = 91643971 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91643971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1832855 + ... + 1832904.

It is an arithmetic number, because the mean of its divisors is an integer number (18939760).

Almost surely, 2^91643975 is an apocalyptic number.

91643975 is a deficient number, since it is larger than the sum of its proper divisors (21994585).

91643975 is a wasteful number, since it uses less digits than its factorization.

91643975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3665769 (or 3665764 counting only the distinct ones).

The product of its digits is 204120, while the sum is 44.

The square root of 91643975 is about 9573.0859705740. The cubic root of 91643975 is about 450.8526631827.

The spelling of 91643975 in words is "ninety-one million, six hundred forty-three thousand, nine hundred seventy-five".