644444446 has 4 divisors (see below), whose sum is σ = 966666672. Its totient is φ = 322222222.

The previous prime is 644444431. The next prime is 644444459.

644444446 is nontrivially palindromic in base 10.

644444446 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a junction number, because it is equal to n+sod(n) for n = 644444399 and 644444408.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161111110 + ... + 161111113.

It is an arithmetic number, because the mean of its divisors is an integer number (241666668).

Almost surely, 2^644444446 is an apocalyptic number.

644444446 is a deficient number, since it is larger than the sum of its proper divisors (322222226).

644444446 is a wasteful number, since it uses less digits than its factorization.

644444446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322222225.

The product of its digits is 589824, while the sum is 40.

The square root of 644444446 is about 25385.9103835179. The cubic root of 644444446 is about 863.7641236749.

The spelling of 644444446 in words is "six hundred forty-four million, four hundred forty-four thousand, four hundred forty-six".