638863786407 has 64 divisors (see below), whose sum is σ = 1071204507648. Its totient is φ = 329008368000.

The previous prime is 638863786361. The next prime is 638863786417. The reversal of 638863786407 is 704687368836.

It is not a de Polignac number, because 638863786407 - 2⁷ = 638863786279 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638863786417) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 31188853 + ... + 31209329.

It is an arithmetic number, because the mean of its divisors is an integer number (16737570432).

Almost surely, 2^638863786407 is an apocalyptic number.

638863786407 is a deficient number, since it is larger than the sum of its proper divisors (432340721241).

638863786407 is a wasteful number, since it uses less digits than its factorization.

638863786407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21660.

The product of its (nonzero) digits is 195084288, while the sum is 66.

The spelling of 638863786407 in words is "six hundred thirty-eight billion, eight hundred sixty-three million, seven hundred eighty-six thousand, four hundred seven".