644463782 has 16 divisors (see below), whose sum is σ = 994157712. Its totient is φ = 313191840.

The previous prime is 644463773. The next prime is 644463811. The reversal of 644463782 is 287364446.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17069 + ... + 39752.

It is an arithmetic number, because the mean of its divisors is an integer number (62134857).

Almost surely, 2^644463782 is an apocalyptic number.

644463782 is a deficient number, since it is larger than the sum of its proper divisors (349693930).

644463782 is a wasteful number, since it uses less digits than its factorization.

644463782 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56983.

The product of its digits is 774144, while the sum is 44.

The square root of 644463782 is about 25386.2912218386. The cubic root of 644463782 is about 863.7727624211.

The spelling of 644463782 in words is "six hundred forty-four million, four hundred sixty-three thousand, seven hundred eighty-two".