639666647144 has 64 divisors (see below), whose sum is σ = 1457682739200. Its totient is φ = 256890000384.

The previous prime is 639666647077. The next prime is 639666647167. The reversal of 639666647144 is 441746666936.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1249064 + ... + 1685079.

It is an arithmetic number, because the mean of its divisors is an integer number (22776292800).

Almost surely, 2^639666647144 is an apocalyptic number.

It is an amenable number.

639666647144 is an abundant number, since it is smaller than the sum of its proper divisors (818016092056).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

639666647144 is a wasteful number, since it uses less digits than its factorization.

639666647144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2934402 (or 2934398 counting only the distinct ones).

The product of its digits is 94058496, while the sum is 62.

The spelling of 639666647144 in words is "six hundred thirty-nine billion, six hundred sixty-six million, six hundred forty-seven thousand, one hundred forty-four".