644051120 has 80 divisors (see below), whose sum is σ = 1590567840. Its totient is φ = 241692672.

The previous prime is 644051077. The next prime is 644051143. The reversal of 644051120 is 21150446.

644051120 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

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, 601946 + ... + 603014.

It is an arithmetic number, because the mean of its divisors is an integer number (19882098).

Almost surely, 2^644051120 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 644051120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (795283920).

644051120 is an abundant number, since it is smaller than the sum of its proper divisors (946516720).

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

644051120 is a wasteful number, since it uses less digits than its factorization.

644051120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1542 (or 1536 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 644051120 is about 25378.1622660113. The cubic root of 644051120 is about 863.5883598669.

The spelling of 644051120 in words is "six hundred forty-four million, fifty-one thousand, one hundred twenty".