644579975446 has 16 divisors (see below), whose sum is σ = 1060067577600. Its totient is φ = 291518579880.

The previous prime is 644579975443. The next prime is 644579975453.

It is a happy number.

644579975446 is nontrivially palindromic in base 10.

644579975446 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644579975443) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 73611426 + ... + 73620181.

It is an arithmetic number, because the mean of its divisors is an integer number (66254223600).

Almost surely, 2^644579975446 is an apocalyptic number.

644579975446 is a deficient number, since it is larger than the sum of its proper divisors (415487602154).

644579975446 is a wasteful number, since it uses less digits than its factorization.

644579975446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147231819.

The product of its digits is 914457600, while the sum is 70.

The spelling of 644579975446 in words is "six hundred forty-four billion, five hundred seventy-nine million, nine hundred seventy-five thousand, four hundred forty-six".