644412608 has 112 divisors (see below), whose sum is σ = 1559015424. Its totient is φ = 257986560.

The previous prime is 644412553. The next prime is 644412617. The reversal of 644412608 is 806214446.

It is a tau number, because it is divible by the number of its divisors (112).

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 15 ways as a sum of consecutive naturals, for example, 1454435 + ... + 1454877.

Almost surely, 2^644412608 is an apocalyptic number.

644412608 is a gapful number since it is divisible by the number (68) 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 644412608, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (779507712).

644412608 is an abundant number, since it is smaller than the sum of its proper divisors (914602816).

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

644412608 is a wasteful number, since it uses less digits than its factorization.

644412608 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 670 (or 660 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 35.

The square root of 644412608 is about 25385.2832956420. The cubic root of 644412608 is about 863.7498990326.

The spelling of 644412608 in words is "six hundred forty-four million, four hundred twelve thousand, six hundred eight".