644666446 has 8 divisors (see below), whose sum is σ = 967215960. Its totient is φ = 322261128.

The previous prime is 644666443. The next prime is 644666459.

644666446 is nontrivially palindromic in base 10.

644666446 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 644666396 and 644666405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644666443) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24076 + ... + 43231.

It is an arithmetic number, because the mean of its divisors is an integer number (120901995).

Almost surely, 2^644666446 is an apocalyptic number.

644666446 is a deficient number, since it is larger than the sum of its proper divisors (322549514).

644666446 is a wasteful number, since it uses less digits than its factorization.

644666446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72098.

The product of its digits is 1990656, while the sum is 46.

The square root of 644666446 is about 25390.2825112286. The cubic root of 644666446 is about 863.8632962371.

The spelling of 644666446 in words is "six hundred forty-four million, six hundred sixty-six thousand, four hundred forty-six".