644053830 has 256 divisors, whose sum is σ = 1981808640. Its totient is φ = 130636800.

The previous prime is 644053829. The next prime is 644053867. The reversal of 644053830 is 38350446.

It is a junction number, because it is equal to n+sod(n) for n = 644053791 and 644053800.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 5071227 + ... + 5071353.

It is an arithmetic number, because the mean of its divisors is an integer number (7741440).

Almost surely, 2^644053830 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644053830, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (990904320).

644053830 is an abundant number, since it is smaller than the sum of its proper divisors (1337754810).

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

644053830 is a wasteful number, since it uses less digits than its factorization.

644053830 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235.

The product of its (nonzero) digits is 34560, while the sum is 33.

The square root of 644053830 is about 25378.2156583161. The cubic root of 644053830 is about 863.5895711171.

The spelling of 644053830 in words is "six hundred forty-four million, fifty-three thousand, eight hundred thirty".