644648472 has 144 divisors (see below), whose sum is σ = 1952683200. Its totient is φ = 191842560.

The previous prime is 644648461. The next prime is 644648513. The reversal of 644648472 is 274846446.

644648472 is a `hidden beast` number, since 64 + 46 + 484 + 72 = 666.

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 35 ways as a sum of consecutive naturals, for example, 376354 + ... + 378062.

It is an arithmetic number, because the mean of its divisors is an integer number (13560300).

Almost surely, 2^644648472 is an apocalyptic number.

644648472 is a gapful number since it is divisible by the number (62) 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 644648472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (976341600).

644648472 is an abundant number, since it is smaller than the sum of its proper divisors (1308034728).

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

644648472 is a wasteful number, since it uses less digits than its factorization.

644648472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1778 (or 1758 counting only the distinct ones).

The product of its digits is 1032192, while the sum is 45.

The square root of 644648472 is about 25389.9285544485. The cubic root of 644648472 is about 863.8552676805.

The spelling of 644648472 in words is "six hundred forty-four million, six hundred forty-eight thousand, four hundred seventy-two".