638403588681 has 8 divisors (see below), whose sum is σ = 878663003904. Its totient is φ = 411873282960.

The previous prime is 638403588659. The next prime is 638403588751. The reversal of 638403588681 is 186885304836.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 638403588681 - 2¹¹ = 638403586633 is a prime.

It is a super-2 number, since 2×638403588681² (a number of 24 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (60) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (638403588611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3432277266 + ... + 3432277451.

It is an arithmetic number, because the mean of its divisors is an integer number (109832875488).

Almost surely, 2^638403588681 is an apocalyptic number.

It is an amenable number.

638403588681 is a deficient number, since it is larger than the sum of its proper divisors (240259415223).

638403588681 is a wasteful number, since it uses less digits than its factorization.

638403588681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6864554751.

The product of its (nonzero) digits is 26542080, while the sum is 60.

The spelling of 638403588681 in words is "six hundred thirty-eight billion, four hundred three million, five hundred eighty-eight thousand, six hundred eighty-one".