820565017 has 2 divisors, whose sum is σ = 820565018. Its totient is φ = 820565016.

The previous prime is 820564999. The next prime is 820565033. The reversal of 820565017 is 710565028.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 771228441 + 49336576 = 27771^2 + 7024^2 .

It is a cyclic number.

It is not a de Polignac number, because 820565017 - 2¹⁵ = 820532249 is a prime.

It is not a weakly prime, because it can be changed into another prime (820565077) 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, 410282508 + 410282509.

It is an arithmetic number, because the mean of its divisors is an integer number (410282509).

Almost surely, 2^820565017 is an apocalyptic number.

It is an amenable number.

820565017 is a deficient number, since it is larger than the sum of its proper divisors (1).

820565017 is an equidigital number, since it uses as much as digits as its factorization.

820565017 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16800, while the sum is 34.

The square root of 820565017 is about 28645.5060524334. The cubic root of 820565017 is about 936.2050927746.

The spelling of 820565017 in words is "eight hundred twenty million, five hundred sixty-five thousand, seventeen".