644346643446 has 256 divisors, whose sum is σ = 1706140800000. Its totient is φ = 178057958400.

The previous prime is 644346643441. The next prime is 644346643453.

644346643446 is a `hidden beast` number, since 64 + 43 + 4 + 66 + 43 + 446 = 666.

644346643446 is nontrivially palindromic in base 10.

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

It is a junction number, because it is equal to n+sod(n) for n = 644346643392 and 644346643401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644346643441) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 114222786 + ... + 114228426.

It is an arithmetic number, because the mean of its divisors is an integer number (6664612500).

Almost surely, 2^644346643446 is an apocalyptic number.

644346643446 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 644346643446, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (853070400000).

644346643446 is an abundant number, since it is smaller than the sum of its proper divisors (1061794156554).

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

644346643446 is a wasteful number, since it uses less digits than its factorization.

644346643446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6060 (or 6054 counting only the distinct ones).

The product of its digits is 47775744, while the sum is 54.

The spelling of 644346643446 in words is "six hundred forty-four billion, three hundred forty-six million, six hundred forty-three thousand, four hundred forty-six".