639786166656 has 512 divisors, whose sum is σ = 2141451648000. Its totient is φ = 168169881600.

The previous prime is 639786166639. The next prime is 639786166661. The reversal of 639786166656 is 656661687936.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 840717316 + ... + 840718076.

It is an arithmetic number, because the mean of its divisors is an integer number (4182522750).

Almost surely, 2^639786166656 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639786166656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1070725824000).

639786166656 is an abundant number, since it is smaller than the sum of its proper divisors (1501665481344).

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

639786166656 is a wasteful number, since it uses less digits than its factorization.

639786166656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1303 (or 1277 counting only the distinct ones).

The product of its digits is 352719360, while the sum is 69.

The spelling of 639786166656 in words is "six hundred thirty-nine billion, seven hundred eighty-six million, one hundred sixty-six thousand, six hundred fifty-six".