638681278329 has 12 divisors (see below), whose sum is σ = 923023413936. Its totient is φ = 425564231352.

The previous prime is 638681278309. The next prime is 638681278369. The reversal of 638681278329 is 923872186836.

638681278329 is a `hidden beast` number, since 6 + 38 + 6 + 8 + 1 + 278 + 329 = 666.

It is not a de Polignac number, because 638681278329 - 2⁸ = 638681278073 is a prime.

It is not an unprimeable number, because it can be changed into a prime (638681278309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18589179 + ... + 18623504.

It is an arithmetic number, because the mean of its divisors is an integer number (76918617828).

Almost surely, 2^638681278329 is an apocalyptic number.

It is an amenable number.

638681278329 is a deficient number, since it is larger than the sum of its proper divisors (284342135607).

638681278329 is a wasteful number, since it uses less digits than its factorization.

638681278329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37214596 (or 37214593 counting only the distinct ones).

The product of its digits is 41803776, while the sum is 63.

The spelling of 638681278329 in words is "six hundred thirty-eight billion, six hundred eighty-one million, two hundred seventy-eight thousand, three hundred twenty-nine".