644071676 has 12 divisors (see below), whose sum is σ = 1127323008. Its totient is φ = 321979392.

The previous prime is 644071663. The next prime is 644071699. The reversal of 644071676 is 676170446.

It is a happy number.

644071676 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, 21605 + ... + 41891.

It is an arithmetic number, because the mean of its divisors is an integer number (93943584).

Almost surely, 2^644071676 is an apocalyptic number.

It is an amenable number.

644071676 is a deficient number, since it is larger than the sum of its proper divisors (483251332).

644071676 is a wasteful number, since it uses less digits than its factorization.

644071676 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28228 (or 28226 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 41.

The square root of 644071676 is about 25378.5672566439. The cubic root of 644071676 is about 863.5975474054.

The spelling of 644071676 in words is "six hundred forty-four million, seventy-one thousand, six hundred seventy-six".