644612316 has 48 divisors (see below), whose sum is σ = 1598688000. Its totient is φ = 201578112.

The previous prime is 644612251. The next prime is 644612323. The reversal of 644612316 is 613216446.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9760 + ... + 37208.

It is an arithmetic number, because the mean of its divisors is an integer number (33306000).

Almost surely, 2^644612316 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644612316, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (799344000).

644612316 is an abundant number, since it is smaller than the sum of its proper divisors (954075684).

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

644612316 is a wasteful number, since it uses less digits than its factorization.

644612316 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27578 (or 27576 counting only the distinct ones).

The product of its digits is 20736, while the sum is 33.

The square root of 644612316 is about 25389.2165298577. The cubic root of 644612316 is about 863.8391172066.

The spelling of 644612316 in words is "six hundred forty-four million, six hundred twelve thousand, three hundred sixteen".