644313047040 has 672 divisors, whose sum is σ = 2483451000576. Its totient is φ = 153448611840.

The previous prime is 644313047023. The next prime is 644313047083. The reversal of 644313047040 is 40740313446.

644313047040 is a `hidden beast` number, since 6 + 443 + 130 + 47 + 0 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 644313046986 and 644313047004.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 148559752 + ... + 148564088.

It is an arithmetic number, because the mean of its divisors is an integer number (3695611608).

Almost surely, 2^644313047040 is an apocalyptic number.

644313047040 is a gapful number since it is divisible by the number (60) 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 644313047040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1241725500288).

644313047040 is an abundant number, since it is smaller than the sum of its proper divisors (1839137953536).

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

644313047040 is a wasteful number, since it uses less digits than its factorization.

644313047040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4418 (or 4391 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 36.

The spelling of 644313047040 in words is "six hundred forty-four billion, three hundred thirteen million, forty-seven thousand, forty".