91393891 has 4 divisors (see below), whose sum is σ = 92943000. Its totient is φ = 89844784.

The previous prime is 91393871. The next prime is 91393903. The reversal of 91393891 is 19839319.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19839319 = 1201 ⋅16519.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91393891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91393801) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 774466 + ... + 774583.

It is an arithmetic number, because the mean of its divisors is an integer number (23235750).

Almost surely, 2^91393891 is an apocalyptic number.

91393891 is a deficient number, since it is larger than the sum of its proper divisors (1549109).

91393891 is a wasteful number, since it uses less digits than its factorization.

91393891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1549108.

The product of its digits is 52488, while the sum is 43.

The square root of 91393891 is about 9560.0152196532. The cubic root of 91393891 is about 450.4421842834.

The spelling of 91393891 in words is "ninety-one million, three hundred ninety-three thousand, eight hundred ninety-one".