644530012 has 48 divisors (see below), whose sum is σ = 1348945920. Its totient is φ = 263463552.

The previous prime is 644530001. The next prime is 644530013. The reversal of 644530012 is 210035446.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644530013) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 262173 + ... + 264619.

It is an arithmetic number, because the mean of its divisors is an integer number (28103040).

Almost surely, 2^644530012 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 644530012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (674472960).

644530012 is an abundant number, since it is smaller than the sum of its proper divisors (704415908).

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

644530012 is a wasteful number, since it uses less digits than its factorization.

644530012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2890 (or 2888 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 644530012 is about 25387.5956325131. The cubic root of 644530012 is about 863.8023506938.

Adding to 644530012 its reverse (210035446), we get a palindrome (854565458).

The spelling of 644530012 in words is "six hundred forty-four million, five hundred thirty thousand, twelve".