644613368 has 64 divisors (see below), whose sum is σ = 1404345600. Its totient is φ = 271699200.

The previous prime is 644613367. The next prime is 644613419. The reversal of 644613368 is 863316446.

It is a hoax number, since the sum of its digits (41) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644613367) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1072268 + ... + 1072868.

It is an arithmetic number, because the mean of its divisors is an integer number (21942900).

Almost surely, 2^644613368 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 644613368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (702172800).

644613368 is an abundant number, since it is smaller than the sum of its proper divisors (759732232).

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

644613368 is a wasteful number, since it uses less digits than its factorization.

644613368 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 900 (or 896 counting only the distinct ones).

The product of its digits is 248832, while the sum is 41.

The square root of 644613368 is about 25389.2372473062. The cubic root of 644613368 is about 863.8395871315.

The spelling of 644613368 in words is "six hundred forty-four million, six hundred thirteen thousand, three hundred sixty-eight".