644586685441 has 2 divisors, whose sum is σ = 644586685442. Its totient is φ = 644586685440.

The previous prime is 644586685429. The next prime is 644586685487. The reversal of 644586685441 is 144586685446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 516759699600 + 127826985841 = 718860^2 + 357529^2 .

It is a cyclic number.

It is not a de Polignac number, because 644586685441 - 2⁷ = 644586685313 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 644586685441.

It is not a weakly prime, because it can be changed into another prime (644586685241) 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, 322293342720 + 322293342721.

It is an arithmetic number, because the mean of its divisors is an integer number (322293342721).

Almost surely, 2^644586685441 is an apocalyptic number.

It is an amenable number.

644586685441 is a deficient number, since it is larger than the sum of its proper divisors (1).

644586685441 is an equidigital number, since it uses as much as digits as its factorization.

644586685441 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 88473600, while the sum is 61.

The spelling of 644586685441 in words is "six hundred forty-four billion, five hundred eighty-six million, six hundred eighty-five thousand, four hundred forty-one".