644906552 has 16 divisors (see below), whose sum is σ = 1234928160. Its totient is φ = 315592384.

The previous prime is 644906551. The next prime is 644906567. The reversal of 644906552 is 255609446.

It is a happy number.

644906552 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644906551) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 857213 + ... + 857964.

It is an arithmetic number, because the mean of its divisors is an integer number (77183010).

Almost surely, 2^644906552 is an apocalyptic number.

It is an amenable number.

644906552 is a deficient number, since it is larger than the sum of its proper divisors (590021608).

644906552 is a wasteful number, since it uses less digits than its factorization.

644906552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1715230 (or 1715226 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 41.

The square root of 644906552 is about 25395.0103760562. The cubic root of 644906552 is about 863.9705315452.

The spelling of 644906552 in words is "six hundred forty-four million, nine hundred six thousand, five hundred fifty-two".