91391871 has 4 divisors (see below), whose sum is σ = 121855832. Its totient is φ = 60927912.

The previous prime is 91391863. The next prime is 91391893. The reversal of 91391871 is 17819319.

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

It is not a de Polignac number, because 91391871 - 2³ = 91391863 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 (91391821) 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, 15231976 + ... + 15231981.

It is an arithmetic number, because the mean of its divisors is an integer number (30463958).

Almost surely, 2^91391871 is an apocalyptic number.

91391871 is a deficient number, since it is larger than the sum of its proper divisors (30463961).

91391871 is a wasteful number, since it uses less digits than its factorization.

91391871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30463960.

The product of its digits is 13608, while the sum is 39.

The square root of 91391871 is about 9559.9095707020. The cubic root of 91391871 is about 450.4388656812.

The spelling of 91391871 in words is "ninety-one million, three hundred ninety-one thousand, eight hundred seventy-one".