865665811 has 2 divisors, whose sum is σ = 865665812. Its totient is φ = 865665810.

The previous prime is 865665803. The next prime is 865665817. The reversal of 865665811 is 118566568.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 865665811 - 2³ = 865665803 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (865665817) 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, 432832905 + 432832906.

It is an arithmetic number, because the mean of its divisors is an integer number (432832906).

Almost surely, 2^865665811 is an apocalyptic number.

865665811 is a deficient number, since it is larger than the sum of its proper divisors (1).

865665811 is an equidigital number, since it uses as much as digits as its factorization.

865665811 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 345600, while the sum is 46.

The square root of 865665811 is about 29422.1992889723. The cubic root of 865665811 is about 953.0523470426.

The spelling of 865665811 in words is "eight hundred sixty-five million, six hundred sixty-five thousand, eight hundred eleven".