891091 has 2 divisors, whose sum is σ = 891092. Its totient is φ = 891090.

The previous prime is 891067. The next prime is 891101. The reversal of 891091 is 190198.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 891091 - 2⁷ = 890963 is a prime.

It is not a weakly prime, because it can be changed into another prime (891001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 445545 + 445546.

It is an arithmetic number, because the mean of its divisors is an integer number (445546).

2⁸⁹¹⁰⁹¹ is an apocalyptic number.

891091 is a deficient number, since it is larger than the sum of its proper divisors (1).

891091 is an equidigital number, since it uses as much as digits as its factorization.

891091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 28.

The square root of 891091 is about 943.9761649533. The cubic root of 891091 is about 96.2293057213.

The spelling of 891091 in words is "eight hundred ninety-one thousand, ninety-one".