644321024 has 36 divisors (see below), whose sum is σ = 1304276400. Its totient is φ = 317614080.

The previous prime is 644320993. The next prime is 644321033. The reversal of 644321024 is 420123446.

It is a junction number, because it is equal to n+sod(n) for n = 644320984 and 644321002.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 452 + ... + 35900.

It is an arithmetic number, because the mean of its divisors is an integer number (36229900).

Almost surely, 2^644321024 is an apocalyptic number.

644321024 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644321024, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (652138200).

644321024 is an abundant number, since it is smaller than the sum of its proper divisors (659955376).

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

644321024 is an equidigital number, since it uses as much as digits as its factorization.

644321024 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35536 (or 35522 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 26.

The square root of 644321024 is about 25383.4793517358. The cubic root of 644321024 is about 863.7089783463.

It can be divided in two parts, 64432 and 1024, that added together give a palindrome (65456).

The spelling of 644321024 in words is "six hundred forty-four million, three hundred twenty-one thousand, twenty-four".