644646347 has 2 divisors, whose sum is σ = 644646348. Its totient is φ = 644646346.

The previous prime is 644646319. The next prime is 644646361. The reversal of 644646347 is 743646446.

It is a happy number.

644646347 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 is a cyclic number.

It is not a de Polignac number, because 644646347 - 2⁸ = 644646091 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 644646298 and 644646307.

It is not a weakly prime, because it can be changed into another prime (644646547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322323173 + 322323174.

It is an arithmetic number, because the mean of its divisors is an integer number (322323174).

Almost surely, 2^644646347 is an apocalyptic number.

644646347 is a deficient number, since it is larger than the sum of its proper divisors (1).

644646347 is an equidigital number, since it uses as much as digits as its factorization.

644646347 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1161216, while the sum is 44.

The square root of 644646347 is about 25389.8867071123. The cubic root of 644646347 is about 863.8543184839.

Subtracting 644646347 from its reverse (743646446), we obtain a palindrome (99000099).

The spelling of 644646347 in words is "six hundred forty-four million, six hundred forty-six thousand, three hundred forty-seven".