638886726272 has 128 divisors (see below), whose sum is σ = 1325473578000. Its totient is φ = 306373165056.

The previous prime is 638886726259. The next prime is 638886726293. The reversal of 638886726272 is 272627688836.

It can be written as a sum of positive squares in 8 ways, for example, as 635872277056 + 3014449216 = 797416^2 + 54904^2 .

It is a tau number, because it is divible by the number of its divisors (128).

It is a junction number, because it is equal to n+sod(n) for n = 638886726199 and 638886726208.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 728490698 + ... + 728491574.

Almost surely, 2^638886726272 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 638886726272, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (662736789000).

638886726272 is an abundant number, since it is smaller than the sum of its proper divisors (686586851728).

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

638886726272 is a wasteful number, since it uses less digits than its factorization.

638886726272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2006 (or 1994 counting only the distinct ones).

The product of its digits is 130056192, while the sum is 65.

The spelling of 638886726272 in words is "six hundred thirty-eight billion, eight hundred eighty-six million, seven hundred twenty-six thousand, two hundred seventy-two".