644883713 has 2 divisors, whose sum is σ = 644883714. Its totient is φ = 644883712.

The previous prime is 644883709. The next prime is 644883719. The reversal of 644883713 is 317388446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 360354289 + 284529424 = 18983^2 + 16868^2 .

It is a cyclic number.

It is not a de Polignac number, because 644883713 - 2² = 644883709 is a prime.

It is not a weakly prime, because it can be changed into another prime (644883719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322441856 + 322441857.

It is an arithmetic number, because the mean of its divisors is an integer number (322441857).

Almost surely, 2^644883713 is an apocalyptic number.

It is an amenable number.

644883713 is a deficient number, since it is larger than the sum of its proper divisors (1).

644883713 is an equidigital number, since it uses as much as digits as its factorization.

644883713 is an evil number, because the sum of its binary digits is even.

The product of its digits is 387072, while the sum is 44.

The square root of 644883713 is about 25394.5606971257. The cubic root of 644883713 is about 863.9603324159.

The spelling of 644883713 in words is "six hundred forty-four million, eight hundred eighty-three thousand, seven hundred thirteen".