644244825 has 24 divisors (see below), whose sum is σ = 1217316928. Its totient is φ = 294511680.

The previous prime is 644244793. The next prime is 644244847. The reversal of 644244825 is 528442446.

644244825 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 644244825 - 2⁵ = 644244793 is a prime.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 613042 + ... + 614091.

Almost surely, 2^644244825 is an apocalyptic number.

It is an amenable number.

644244825 is a deficient number, since it is larger than the sum of its proper divisors (573072103).

644244825 is a wasteful number, since it uses less digits than its factorization.

644244825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1227153 (or 1227148 counting only the distinct ones).

The product of its digits is 245760, while the sum is 39.

The square root of 644244825 is about 25381.9783507905. The cubic root of 644244825 is about 863.6749288831.

The spelling of 644244825 in words is "six hundred forty-four million, two hundred forty-four thousand, eight hundred twenty-five".