8211809 has 2 divisors, whose sum is σ = 8211810. Its totient is φ = 8211808.

The previous prime is 8211803. The next prime is 8211821. The reversal of 8211809 is 9081128.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6838225 + 1373584 = 2615^2 + 1172^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8211809 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (8211803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4105904 + 4105905.

It is an arithmetic number, because the mean of its divisors is an integer number (4105905).

Almost surely, 2^8211809 is an apocalyptic number.

It is an amenable number.

8211809 is a deficient number, since it is larger than the sum of its proper divisors (1).

8211809 is an equidigital number, since it uses as much as digits as its factorization.

8211809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 29.

The square root of 8211809 is about 2865.6254116685. The cubic root of 8211809 is about 201.7497227119.

The spelling of 8211809 in words is "eight million, two hundred eleven thousand, eight hundred nine".