644466048 has 64 divisors (see below), whose sum is σ = 1716211200. Its totient is φ = 214276608.

The previous prime is 644466047. The next prime is 644466079. The reversal of 644466048 is 840664446.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644466041) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 166665 + ... + 170487.

It is an arithmetic number, because the mean of its divisors is an integer number (26815800).

Almost surely, 2^644466048 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 644466048, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (858105600).

644466048 is an abundant number, since it is smaller than the sum of its proper divisors (1071745152).

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

644466048 is a wasteful number, since it uses less digits than its factorization.

644466048 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4279 (or 4267 counting only the distinct ones).

The product of its (nonzero) digits is 442368, while the sum is 42.

The square root of 644466048 is about 25386.3358521863. The cubic root of 644466048 is about 863.7737747908.

The spelling of 644466048 in words is "six hundred forty-four million, four hundred sixty-six thousand, forty-eight".