638841332321 has 2 divisors, whose sum is σ = 638841332322. Its totient is φ = 638841332320.

The previous prime is 638841332309. The next prime is 638841332333. The reversal of 638841332321 is 123233148836.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (638841332309) and next prime (638841332333).

It can be written as a sum of positive squares in only one way, i.e., 582878806225 + 55962526096 = 763465^2 + 236564^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638841332321 is a prime.

It is not a weakly prime, because it can be changed into another prime (638841302321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319420666160 + 319420666161.

It is an arithmetic number, because the mean of its divisors is an integer number (319420666161).

Almost surely, 2^638841332321 is an apocalyptic number.

It is an amenable number.

638841332321 is a deficient number, since it is larger than the sum of its proper divisors (1).

638841332321 is an equidigital number, since it uses as much as digits as its factorization.

638841332321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 497664, while the sum is 44.

The spelling of 638841332321 in words is "six hundred thirty-eight billion, eight hundred forty-one million, three hundred thirty-two thousand, three hundred twenty-one".