644012506654512 has 40 divisors (see below), whose sum is σ = 1761563621145456. Its totient is φ = 202043139342336.

The previous prime is 644012506654499. The next prime is 644012506654513. The reversal of 644012506654512 is 215456605210446.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is not an unprimeable number, because it can be changed into a prime (644012506654513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 394615505713 + ... + 394615507344.

Almost surely, 2^{644012506654512} is an apocalyptic number.

It is an amenable number.

644012506654512 is an abundant number, since it is smaller than the sum of its proper divisors (1117551114490944).

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

644012506654512 is a wasteful number, since it uses less digits than its factorization.

644012506654512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 789231013085 (or 789231013079 counting only the distinct ones).

The product of its (nonzero) digits is 6912000, while the sum is 51.

The spelling of 644012506654512 in words is "six hundred forty-four trillion, twelve billion, five hundred six million, six hundred fifty-four thousand, five hundred twelve".