644606446 has 24 divisors (see below), whose sum is σ = 1066546152. Its totient is φ = 291970800.

The previous prime is 644606437. The next prime is 644606453.

It is a happy number.

644606446 is nontrivially palindromic in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 644606399 and 644606408.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 66361 + ... + 75451.

It is an arithmetic number, because the mean of its divisors is an integer number (44439423).

Almost surely, 2^644606446 is an apocalyptic number.

644606446 is a deficient number, since it is larger than the sum of its proper divisors (421939706).

644606446 is a wasteful number, since it uses less digits than its factorization.

644606446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9408 (or 9397 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 40.

The square root of 644606446 is about 25389.1009293358. The cubic root of 644606446 is about 863.8364950874.

The spelling of 644606446 in words is "six hundred forty-four million, six hundred six thousand, four hundred forty-six".