644909446 has 8 divisors (see below), whose sum is σ = 983222784. Its totient is φ = 317168520.

The previous prime is 644909423. The next prime is 644909479.

644909446 is nontrivially palindromic in base 10.

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 = 644909396 and 644909405.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2642950 + ... + 2643193.

It is an arithmetic number, because the mean of its divisors is an integer number (122902848).

Almost surely, 2^644909446 is an apocalyptic number.

644909446 is a deficient number, since it is larger than the sum of its proper divisors (338313338).

644909446 is a wasteful number, since it uses less digits than its factorization.

644909446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5286206.

The product of its (nonzero) digits is 746496, while the sum is 46.

The square root of 644909446 is about 25395.0673556894. The cubic root of 644909446 is about 863.9718238911.

The spelling of 644909446 in words is "six hundred forty-four million, nine hundred nine thousand, four hundred forty-six".