644525424 has 120 divisors (see below), whose sum is σ = 1890972720. Its totient is φ = 212502528.

The previous prime is 644525423. The next prime is 644525447. The reversal of 644525424 is 424525446.

644525424 is a `hidden beast` number, since 64 + 4 + 52 + 542 + 4 = 666.

644525424 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 (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644525423) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 376282 + ... + 377990.

It is an arithmetic number, because the mean of its divisors is an integer number (15758106).

Almost surely, 2^644525424 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 644525424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (945486360).

644525424 is an abundant number, since it is smaller than the sum of its proper divisors (1246447296).

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

644525424 is a wasteful number, since it uses less digits than its factorization.

644525424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1829 (or 1811 counting only the distinct ones).

The product of its digits is 153600, while the sum is 36.

The square root of 644525424 is about 25387.5052732639. The cubic root of 644525424 is about 863.8003010688.

The spelling of 644525424 in words is "six hundred forty-four million, five hundred twenty-five thousand, four hundred twenty-four".