644727216675 has 24 divisors (see below), whose sum is σ = 1065977202160. Its totient is φ = 343845417600.

The previous prime is 644727216589. The next prime is 644727216677. The reversal of 644727216675 is 576612727446.

It is not a de Polignac number, because 644727216675 - 2⁷ = 644727216547 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644727216677) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3500385 + ... + 3679965.

Almost surely, 2^644727216675 is an apocalyptic number.

644727216675 is a deficient number, since it is larger than the sum of its proper divisors (421249985485).

644727216675 is a wasteful number, since it uses less digits than its factorization.

644727216675 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227463 (or 227458 counting only the distinct ones).

The product of its digits is 23708160, while the sum is 57.

The spelling of 644727216675 in words is "six hundred forty-four billion, seven hundred twenty-seven million, two hundred sixteen thousand, six hundred seventy-five".