820582788721 has 2 divisors, whose sum is σ = 820582788722. Its totient is φ = 820582788720.

The previous prime is 820582788691. The next prime is 820582788761. The reversal of 820582788721 is 127887285028.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 487727640625 + 332855148096 = 698375^2 + 576936^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-820582788721 is a prime.

It is a super-3 number, since 3×820582788721³ (a number of 37 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (820582788761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410291394360 + 410291394361.

It is an arithmetic number, because the mean of its divisors is an integer number (410291394361).

Almost surely, 2^820582788721 is an apocalyptic number.

It is an amenable number.

820582788721 is a deficient number, since it is larger than the sum of its proper divisors (1).

820582788721 is an equidigital number, since it uses as much as digits as its factorization.

820582788721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8028160, while the sum is 58.

The spelling of 820582788721 in words is "eight hundred twenty billion, five hundred eighty-two million, seven hundred eighty-eight thousand, seven hundred twenty-one".