644382432 has 96 divisors (see below), whose sum is σ = 1885716000. Its totient is φ = 214078464.

The previous prime is 644382419. The next prime is 644382437. The reversal of 644382432 is 234283446.

644382432 is a `hidden beast` number, since 644 + 3 + 8 + 2 + 4 + 3 + 2 = 666.

644382432 is digitally balanced in base 2, 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 (96).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644382437) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 300468 + ... + 302604.

It is an arithmetic number, because the mean of its divisors is an integer number (19642875).

Almost surely, 2^644382432 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 644382432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (942858000).

644382432 is an abundant number, since it is smaller than the sum of its proper divisors (1241333568).

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

644382432 is a wasteful number, since it uses less digits than its factorization.

644382432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2505 (or 2491 counting only the distinct ones).

The product of its digits is 110592, while the sum is 36.

The square root of 644382432 is about 25384.6889285648. The cubic root of 644382432 is about 863.7364165094.

The spelling of 644382432 in words is "six hundred forty-four million, three hundred eighty-two thousand, four hundred thirty-two".