81091711 has 2 divisors, whose sum is σ = 81091712. Its totient is φ = 81091710.

The previous prime is 81091687. The next prime is 81091729. The reversal of 81091711 is 11719018.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81091711 - 2¹⁷ = 80960639 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81091711.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81091741) 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 as a sum of consecutive naturals, namely, 40545855 + 40545856.

It is an arithmetic number, because the mean of its divisors is an integer number (40545856).

Almost surely, 2^81091711 is an apocalyptic number.

81091711 is a deficient number, since it is larger than the sum of its proper divisors (1).

81091711 is an equidigital number, since it uses as much as digits as its factorization.

81091711 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 504, while the sum is 28.

The square root of 81091711 is about 9005.0936141719. The cubic root of 81091711 is about 432.8381059829.

The spelling of 81091711 in words is "eighty-one million, ninety-one thousand, seven hundred eleven".