644830854912 has 360 divisors, whose sum is σ = 2062222137360. Its totient is φ = 199782236160.

The previous prime is 644830854887. The next prime is 644830854917. The reversal of 644830854912 is 219458038446.

644830854912 is a `hidden beast` number, since 6 + 4 + 4 + 83 + 0 + 8 + 549 + 12 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644830854917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 20865712 + ... + 20896592.

It is an arithmetic number, because the mean of its divisors is an integer number (5728394826).

Almost surely, 2^644830854912 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 644830854912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1031111068680).

644830854912 is an abundant number, since it is smaller than the sum of its proper divisors (1417391282448).

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

644830854912 is a wasteful number, since it uses less digits than its factorization.

644830854912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30981 (or 30958 counting only the distinct ones).

The product of its (nonzero) digits is 6635520, while the sum is 54.

The spelling of 644830854912 in words is "six hundred forty-four billion, eight hundred thirty million, eight hundred fifty-four thousand, nine hundred twelve".