644066642 has 16 divisors (see below), whose sum is σ = 995134272. Its totient is φ = 312454800.

The previous prime is 644066639. The next prime is 644066651. The reversal of 644066642 is 246660446.

644066642 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 644066596 and 644066605.

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, 11813 + ... + 37784.

It is an arithmetic number, because the mean of its divisors is an integer number (62195892).

Almost surely, 2^644066642 is an apocalyptic number.

644066642 is a deficient number, since it is larger than the sum of its proper divisors (351067630).

644066642 is a wasteful number, since it uses less digits than its factorization.

644066642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49793.

The product of its (nonzero) digits is 165888, while the sum is 38.

The square root of 644066642 is about 25378.4680782745. The cubic root of 644066642 is about 863.5952974688.

The spelling of 644066642 in words is "six hundred forty-four million, sixty-six thousand, six hundred forty-two".