644306322 has 64 divisors (see below), whose sum is σ = 1435107456. Its totient is φ = 191208960.

The previous prime is 644306317. The next prime is 644306323. The reversal of 644306322 is 223603446.

It is a happy number.

644306322 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 644306322.

It is not an unprimeable number, because it can be changed into a prime (644306323) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 833128 + ... + 833900.

It is an arithmetic number, because the mean of its divisors is an integer number (22423554).

Almost surely, 2^644306322 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644306322, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (717553728).

644306322 is an abundant number, since it is smaller than the sum of its proper divisors (790801134).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644306322 is a wasteful number, since it uses less digits than its factorization.

644306322 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1035.

The product of its (nonzero) digits is 20736, while the sum is 30.

The square root of 644306322 is about 25383.1897522750. The cubic root of 644306322 is about 863.7024089782.

Adding to 644306322 its reverse (223603446), we get a palindrome (867909768).

The spelling of 644306322 in words is "six hundred forty-four million, three hundred six thousand, three hundred twenty-two".