644195552 has 288 divisors, whose sum is σ = 1846061280. Its totient is φ = 218050560.

The previous prime is 644195491. The next prime is 644195557. The reversal of 644195552 is 255591446.

Its product of digits (216000) is a multiple of the sum of its prime divisors (50).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644195557) 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 47 ways as a sum of consecutive naturals, for example, 37893848 + ... + 37893864.

It is an arithmetic number, because the mean of its divisors is an integer number (6409935).

Almost surely, 2^644195552 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 644195552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (923030640).

644195552 is an abundant number, since it is smaller than the sum of its proper divisors (1201865728).

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

644195552 is a wasteful number, since it uses less digits than its factorization.

644195552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91 (or 50 counting only the distinct ones).

The product of its digits is 216000, while the sum is 41.

The square root of 644195552 is about 25381.0077026110. The cubic root of 644195552 is about 863.6529098524.

The spelling of 644195552 in words is "six hundred forty-four million, one hundred ninety-five thousand, five hundred fifty-two".