644674193 has 2 divisors, whose sum is σ = 644674194. Its totient is φ = 644674192.

The previous prime is 644674181. The next prime is 644674211. The reversal of 644674193 is 391476446.

644674193 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., 411562369 + 233111824 = 20287^2 + 15268^2 .

It is a cyclic number.

It is not a de Polignac number, because 644674193 - 2⁸ = 644673937 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (644674993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322337096 + 322337097.

It is an arithmetic number, because the mean of its divisors is an integer number (322337097).

Almost surely, 2^644674193 is an apocalyptic number.

It is an amenable number.

644674193 is a deficient number, since it is larger than the sum of its proper divisors (1).

644674193 is an equidigital number, since it uses as much as digits as its factorization.

644674193 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 435456, while the sum is 44.

The square root of 644674193 is about 25390.4350691358. The cubic root of 644674193 is about 863.8667565910.

The spelling of 644674193 in words is "six hundred forty-four million, six hundred seventy-four thousand, one hundred ninety-three".