91091081 has 2 divisors, whose sum is σ = 91091082. Its totient is φ = 91091080.

The previous prime is 91091041. The next prime is 91091129. The reversal of 91091081 is 18019019.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 71554681 + 19536400 = 8459^2 + 4420^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91091081 is a prime.

It is a super-3 number, since 3×91091081³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (91091041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45545540 + 45545541.

It is an arithmetic number, because the mean of its divisors is an integer number (45545541).

Almost surely, 2^91091081 is an apocalyptic number.

It is an amenable number.

91091081 is a deficient number, since it is larger than the sum of its proper divisors (1).

91091081 is an equidigital number, since it uses as much as digits as its factorization.

91091081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 29.

The square root of 91091081 is about 9544.1647617798. The cubic root of 91091081 is about 449.9441593261.

The spelling of 91091081 in words is "ninety-one million, ninety-one thousand, eighty-one".