644355212233 has 2 divisors, whose sum is σ = 644355212234. Its totient is φ = 644355212232.

The previous prime is 644355212227. The next prime is 644355212297. The reversal of 644355212233 is 332212553446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 523326368569 + 121028843664 = 723413^2 + 347892^2 .

It is a cyclic number.

It is not a de Polignac number, because 644355212233 - 2⁵ = 644355212201 is a prime.

It is not a weakly prime, because it can be changed into another prime (644355212833) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322177606116 + 322177606117.

It is an arithmetic number, because the mean of its divisors is an integer number (322177606117).

Almost surely, 2^644355212233 is an apocalyptic number.

It is an amenable number.

644355212233 is a deficient number, since it is larger than the sum of its proper divisors (1).

644355212233 is an equidigital number, since it uses as much as digits as its factorization.

644355212233 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 518400, while the sum is 40.

Adding to 644355212233 its reverse (332212553446), we get a palindrome (976567765679).

The spelling of 644355212233 in words is "six hundred forty-four billion, three hundred fifty-five million, two hundred twelve thousand, two hundred thirty-three".