644575490089 has 2 divisors, whose sum is σ = 644575490090. Its totient is φ = 644575490088.

The previous prime is 644575490087. The next prime is 644575490161. The reversal of 644575490089 is 980094575446.

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., 628270243225 + 16305246864 = 792635^2 + 127692^2 .

It is a cyclic number.

It is not a de Polignac number, because 644575490089 - 2¹ = 644575490087 is a prime.

Together with 644575490087, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (644575490081) 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, 322287745044 + 322287745045.

It is an arithmetic number, because the mean of its divisors is an integer number (322287745045).

Almost surely, 2^644575490089 is an apocalyptic number.

It is an amenable number.

644575490089 is a deficient number, since it is larger than the sum of its proper divisors (1).

644575490089 is an equidigital number, since it uses as much as digits as its factorization.

644575490089 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 43545600, while the sum is 61.

The spelling of 644575490089 in words is "six hundred forty-four billion, five hundred seventy-five million, four hundred ninety thousand, eighty-nine".