91081 has 2 divisors, whose sum is σ = 91082. Its totient is φ = 91080.

The previous prime is 91079. The next prime is 91097. The reversal of 91081 is 18019.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 84681 + 6400 = 291^2 + 80^2 .

It is a cyclic number.

It is not a de Polignac number, because 91081 - 2¹ = 91079 is a prime.

It is a super-2 number, since 2×91081² = 16591497122, which contains 22 as substring.

Together with 91079, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (91381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45540 + 45541.

It is an arithmetic number, because the mean of its divisors is an integer number (45541).

2⁹¹⁰⁸¹ is an apocalyptic number.

It is an amenable number.

91081 is a deficient number, since it is larger than the sum of its proper divisors (1).

91081 is an equidigital number, since it uses as much as digits as its factorization.

91081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 19.

The square root of 91081 is about 301.7962889103. The cubic root of 91081 is about 44.9927560356.

The spelling of 91081 in words is "ninety-one thousand, eighty-one".