644614004736 has 896 divisors, whose sum is σ = 2167085571840. Its totient is φ = 188045328384.

The previous prime is 644614004717. The next prime is 644614004833. The reversal of 644614004736 is 637400416446.

It is a junction number, because it is equal to n+sod(n) for n = 644614004691 and 644614004700.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 7766433751 + ... + 7766433833.

It is an arithmetic number, because the mean of its divisors is an integer number (2418622290).

Almost surely, 2^644614004736 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 644614004736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1083542785920).

644614004736 is an abundant number, since it is smaller than the sum of its proper divisors (1522471567104).

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

644614004736 is a wasteful number, since it uses less digits than its factorization.

644614004736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241 (or 211 counting only the distinct ones).

The product of its (nonzero) digits is 1161216, while the sum is 45.

The spelling of 644614004736 in words is "six hundred forty-four billion, six hundred fourteen million, four thousand, seven hundred thirty-six".