644502534912 has 576 divisors, whose sum is σ = 2161289625600. Its totient is φ = 188370800640.

The previous prime is 644502534869. The next prime is 644502534913. The reversal of 644502534912 is 219435205446.

644502534912 is a `hidden beast` number, since 6 + 4 + 4 + 502 + 53 + 4 + 91 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

It is not an unprimeable number, because it can be changed into a prime (644502534913) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 93633423 + ... + 93640305.

Almost surely, 2^644502534912 is an apocalyptic number.

644502534912 is a gapful number since it is divisible by the number (62) 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 644502534912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1080644812800).

644502534912 is an abundant number, since it is smaller than the sum of its proper divisors (1516787090688).

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

644502534912 is a wasteful number, since it uses less digits than its factorization.

644502534912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6981 (or 6961 counting only the distinct ones).

The product of its (nonzero) digits is 1036800, while the sum is 45.

The spelling of 644502534912 in words is "six hundred forty-four billion, five hundred two million, five hundred thirty-four thousand, nine hundred twelve".