644956847 has 2 divisors, whose sum is σ = 644956848. Its totient is φ = 644956846.

The previous prime is 644956813. The next prime is 644956853. The reversal of 644956847 is 748659446.

644956847 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 644956847 - 2¹⁰ = 644955823 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644956877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322478423 + 322478424.

It is an arithmetic number, because the mean of its divisors is an integer number (322478424).

Almost surely, 2^644956847 is an apocalyptic number.

644956847 is a deficient number, since it is larger than the sum of its proper divisors (1).

644956847 is an equidigital number, since it uses as much as digits as its factorization.

644956847 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5806080, while the sum is 53.

The square root of 644956847 is about 25396.0006103323. Note that the first 3 decimals coincide. The cubic root of 644956847 is about 863.9929907518.

The spelling of 644956847 in words is "six hundred forty-four million, nine hundred fifty-six thousand, eight hundred forty-seven".