644795483904 has 1728 divisors, whose sum is σ = 2497393866240. Its totient is φ = 156704440320.

The previous prime is 644795483897. The next prime is 644795483963. The reversal of 644795483904 is 409384597446.

It is a happy number.

644795483904 is a `hidden beast` number, since 64 + 4 + 7 + 9 + 5 + 483 + 90 + 4 = 666.

It is a super-2 number, since 2×644795483904² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 7768620247 + ... + 7768620329.

It is an arithmetic number, because the mean of its divisors is an integer number (1445251080).

Almost surely, 2^644795483904 is an apocalyptic number.

644795483904 is a gapful number since it is divisible by the number (64) 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 644795483904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1248696933120).

644795483904 is an abundant number, since it is smaller than the sum of its proper divisors (1852598382336).

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

644795483904 is a wasteful number, since it uses less digits than its factorization.

644795483904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238 (or 221 counting only the distinct ones).

The product of its (nonzero) digits is 104509440, while the sum is 63.

The spelling of 644795483904 in words is "six hundred forty-four billion, seven hundred ninety-five million, four hundred eighty-three thousand, nine hundred four".