644582016 has 128 divisors (see below), whose sum is σ = 2048894400. Its totient is φ = 198319104.

The previous prime is 644581967. The next prime is 644582027. The reversal of 644582016 is 610285446.

644582016 is a `hidden beast` number, since 6 + 445 + 8 + 201 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (128).

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

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37755 + ... + 52101.

Almost surely, 2^644582016 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 644582016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1024447200).

644582016 is an abundant number, since it is smaller than the sum of its proper divisors (1404312384).

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

644582016 is a wasteful number, since it uses less digits than its factorization.

644582016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14383 (or 14365 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 36.

The square root of 644582016 is about 25388.6198128216. The cubic root of 644582016 is about 863.8255820761.

It can be divided in two parts, 644 and 582016, that added together give a triangular number (582660 = T₁₀₇₉).

The spelling of 644582016 in words is "six hundred forty-four million, five hundred eighty-two thousand, sixteen".