644325233 has 2 divisors, whose sum is σ = 644325234. Its totient is φ = 644325232.

The previous prime is 644325221. The next prime is 644325257. The reversal of 644325233 is 332523446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 583125904 + 61199329 = 24148^2 + 7823^2 .

It is a cyclic number.

It is not a de Polignac number, because 644325233 - 2¹⁰ = 644324209 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 644325233.

It is not a weakly prime, because it can be changed into another prime (644325263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322162616 + 322162617.

It is an arithmetic number, because the mean of its divisors is an integer number (322162617).

Almost surely, 2^644325233 is an apocalyptic number.

It is an amenable number.

644325233 is a deficient number, since it is larger than the sum of its proper divisors (1).

644325233 is an equidigital number, since it uses as much as digits as its factorization.

644325233 is an evil number, because the sum of its binary digits is even.

The product of its digits is 51840, while the sum is 32.

The square root of 644325233 is about 25383.5622598563. The cubic root of 644325233 is about 863.7108590564.

Adding to 644325233 its reverse (332523446), we get a palindrome (976848679).

The spelling of 644325233 in words is "six hundred forty-four million, three hundred twenty-five thousand, two hundred thirty-three".