644313253 has 2 divisors, whose sum is σ = 644313254. Its totient is φ = 644313252.

The previous prime is 644313223. The next prime is 644313287. The reversal of 644313253 is 352313446.

644313253 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 630160609 + 14152644 = 25103^2 + 3762^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644313253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644313203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322156626 + 322156627.

It is an arithmetic number, because the mean of its divisors is an integer number (322156627).

Almost surely, 2^644313253 is an apocalyptic number.

It is an amenable number.

644313253 is a deficient number, since it is larger than the sum of its proper divisors (1).

644313253 is an equidigital number, since it uses as much as digits as its factorization.

644313253 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25920, while the sum is 31.

The square root of 644313253 is about 25383.3262792724. The cubic root of 644313253 is about 863.7055060040.

Adding to 644313253 its reverse (352313446), we get a palindrome (996626699).

The spelling of 644313253 in words is "six hundred forty-four million, three hundred thirteen thousand, two hundred fifty-three".