644596013 has 2 divisors, whose sum is σ = 644596014. Its totient is φ = 644596012.

The previous prime is 644595977. The next prime is 644596019. The reversal of 644596013 is 310695446.

644596013 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 390576169 + 254019844 = 19763^2 + 15938^2 .

It is a cyclic number.

It is not a de Polignac number, because 644596013 - 2¹⁶ = 644530477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644596019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322298006 + 322298007.

It is an arithmetic number, because the mean of its divisors is an integer number (322298007).

Almost surely, 2^644596013 is an apocalyptic number.

It is an amenable number.

644596013 is a deficient number, since it is larger than the sum of its proper divisors (1).

644596013 is an equidigital number, since it uses as much as digits as its factorization.

644596013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 77760, while the sum is 38.

The square root of 644596013 is about 25388.8954663254. The cubic root of 644596013 is about 863.8318346444.

The spelling of 644596013 in words is "six hundred forty-four million, five hundred ninety-six thousand, thirteen".