644352000 has 192 divisors, whose sum is σ = 2146435200. Its totient is φ = 171622400.

The previous prime is 644351977. The next prime is 644352001. The reversal of 644352000 is 253446.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (644352001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 767581 + ... + 768419.

It is an arithmetic number, because the mean of its divisors is an integer number (11179350).

Almost surely, 2^644352000 is an apocalyptic number.

644352000 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644352000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1073217600).

644352000 is an abundant number, since it is smaller than the sum of its proper divisors (1502083200).

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

644352000 is an equidigital number, since it uses as much as digits as its factorization.

644352000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 879 (or 849 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 24.

The square root of 644352000 is about 25384.0895050423. The cubic root of 644352000 is about 863.7228191801.

The spelling of 644352000 in words is "six hundred forty-four million, three hundred fifty-two thousand".