644223332246120 has 256 divisors, whose sum is σ = 1606664296442880. Its totient is φ = 230530834944000.

The previous prime is 644223332246089. The next prime is 644223332246129. The reversal of 644223332246120 is 21642233322446.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is not an unprimeable number, because it can be changed into a prime (644223332246129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 28699740737 + ... + 28699763183.

It is an arithmetic number, because the mean of its divisors is an integer number (6276032407980).

Almost surely, 2^{644223332246120} 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 644223332246120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (803332148221440).

644223332246120 is an abundant number, since it is smaller than the sum of its proper divisors (962440964196760).

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

644223332246120 is a wasteful number, since it uses less digits than its factorization.

644223332246120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26476 (or 26472 counting only the distinct ones).

The product of its (nonzero) digits is 1990656, while the sum is 44.

Adding to 644223332246120 its reverse (21642233322446), we get a palindrome (665865565568566).

The spelling of 644223332246120 in words is "six hundred forty-four trillion, two hundred twenty-three billion, three hundred thirty-two million, two hundred forty-six thousand, one hundred twenty".