644101368 has 128 divisors (see below), whose sum is σ = 1788480000. Its totient is φ = 192471552.

The previous prime is 644101319. The next prime is 644101369. The reversal of 644101368 is 863101446.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644101369) 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, 700413 + ... + 701331.

It is an arithmetic number, because the mean of its divisors is an integer number (13972500).

Almost surely, 2^644101368 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 644101368, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (894240000).

644101368 is an abundant number, since it is smaller than the sum of its proper divisors (1144378632).

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

644101368 is a wasteful number, since it uses less digits than its factorization.

644101368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1029 (or 1025 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 33.

The square root of 644101368 is about 25379.1522317039. The cubic root of 644101368 is about 863.6108179493.

The spelling of 644101368 in words is "six hundred forty-four million, one hundred one thousand, three hundred sixty-eight".