644434120 has 64 divisors (see below), whose sum is σ = 1618626240. Its totient is φ = 228883200.

The previous prime is 644434111. The next prime is 644434121. The reversal of 644434120 is 21434446.

It is not an unprimeable number, because it can be changed into a prime (644434121) 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, 1890 + ... + 35950.

It is an arithmetic number, because the mean of its divisors is an integer number (25291035).

Almost surely, 2^644434120 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 644434120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (809313120).

644434120 is an abundant number, since it is smaller than the sum of its proper divisors (974192120).

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

644434120 is a wasteful number, since it uses less digits than its factorization.

644434120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34126 (or 34122 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 28.

The square root of 644434120 is about 25385.7070021695. The cubic root of 644434120 is about 863.7595102563.

Adding to 644434120 its reverse (21434446), we get a palindrome (665868566).

The spelling of 644434120 in words is "six hundred forty-four million, four hundred thirty-four thousand, one hundred twenty".