91943581 has 4 divisors (see below), whose sum is σ = 95941152. Its totient is φ = 87946012.

The previous prime is 91943567. The next prime is 91943617. The reversal of 91943581 is 18534919.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 91943581 - 2¹⁵ = 91910813 is a prime.

It is a super-2 number, since 2×91943581² = 16907244174207122, which contains 22 as substring.

It is a pancake number, because a pancake can be divided into 91943581 parts by 13560 straight cuts.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91943521) 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, 1998751 + ... + 1998796.

It is an arithmetic number, because the mean of its divisors is an integer number (23985288).

Almost surely, 2^91943581 is an apocalyptic number.

It is an amenable number.

91943581 is a deficient number, since it is larger than the sum of its proper divisors (3997571).

91943581 is a wasteful number, since it uses less digits than its factorization.

91943581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3997570.

The product of its digits is 38880, while the sum is 40.

The square root of 91943581 is about 9588.7215519067. The cubic root of 91943581 is about 451.3434436873.

The spelling of 91943581 in words is "ninety-one million, nine hundred forty-three thousand, five hundred eighty-one".