644323461988 has 24 divisors (see below), whose sum is σ = 1134381528000. Its totient is φ = 320219154528.

The previous prime is 644323461953. The next prime is 644323462001. The reversal of 644323461988 is 889164323446.

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, 38470 + ... + 1135837.

It is an arithmetic number, because the mean of its divisors is an integer number (47265897000).

Almost surely, 2^644323461988 is an apocalyptic number.

It is an amenable number.

644323461988 is a deficient number, since it is larger than the sum of its proper divisors (490058066012).

644323461988 is a wasteful number, since it uses less digits than its factorization.

644323461988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1175139 (or 1175137 counting only the distinct ones).

The product of its digits is 23887872, while the sum is 58.

The spelling of 644323461988 in words is "six hundred forty-four billion, three hundred twenty-three million, four hundred sixty-one thousand, nine hundred eighty-eight".