820664447 has 2 divisors, whose sum is σ = 820664448. Its totient is φ = 820664446.

The previous prime is 820664437. The next prime is 820664483. The reversal of 820664447 is 744466028.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 820664447 - 2⁸ = 820664191 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (820664437) 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, 410332223 + 410332224.

It is an arithmetic number, because the mean of its divisors is an integer number (410332224).

Almost surely, 2^820664447 is an apocalyptic number.

820664447 is a deficient number, since it is larger than the sum of its proper divisors (1).

820664447 is an equidigital number, since it uses as much as digits as its factorization.

820664447 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 258048, while the sum is 41.

The square root of 820664447 is about 28647.2415251451. The cubic root of 820664447 is about 936.2429053837.

The spelling of 820664447 in words is "eight hundred twenty million, six hundred sixty-four thousand, four hundred forty-seven".