644521350 has 96 divisors (see below), whose sum is σ = 1762137216. Its totient is φ = 154598400.

The previous prime is 644521331. The next prime is 644521379. The reversal of 644521350 is 53125446.

644521350 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 158037 + ... + 162063.

It is an arithmetic number, because the mean of its divisors is an integer number (18355596).

Almost surely, 2^644521350 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644521350, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (881068608).

644521350 is an abundant number, since it is smaller than the sum of its proper divisors (1117615866).

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

644521350 is a wasteful number, since it uses less digits than its factorization.

644521350 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4150 (or 4145 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 30.

The square root of 644521350 is about 25387.4250368169. The cubic root of 644521350 is about 863.7984810579.

Adding to 644521350 its reverse (53125446), we get a palindrome (697646796).

The spelling of 644521350 in words is "six hundred forty-four million, five hundred twenty-one thousand, three hundred fifty".