820664291 has 2 divisors, whose sum is σ = 820664292. Its totient is φ = 820664290.

The previous prime is 820664287. The next prime is 820664297. The reversal of 820664291 is 192466028.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 820664291 - 2² = 820664287 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (820664297) 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, 410332145 + 410332146.

It is an arithmetic number, because the mean of its divisors is an integer number (410332146).

Almost surely, 2^820664291 is an apocalyptic number.

820664291 is a deficient number, since it is larger than the sum of its proper divisors (1).

820664291 is an equidigital number, since it uses as much as digits as its factorization.

820664291 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 41472, while the sum is 38.

The square root of 820664291 is about 28647.2388023698. The cubic root of 820664291 is about 936.2428460603.

The spelling of 820664291 in words is "eight hundred twenty million, six hundred sixty-four thousand, two hundred ninety-one".