638378615857 has 8 divisors (see below), whose sum is σ = 641679104000. Its totient is φ = 635079053664.

The previous prime is 638378615837. The next prime is 638378615911. The reversal of 638378615857 is 758516873836.

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

It is a cyclic number.

It is not a de Polignac number, because 638378615857 - 2¹⁹ = 638378091569 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 638378615792 and 638378615801.

It is not an unprimeable number, because it can be changed into a prime (638378615837) 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, 1172893 + ... + 1628629.

It is an arithmetic number, because the mean of its divisors is an integer number (80209888000).

Almost surely, 2^638378615857 is an apocalyptic number.

It is an amenable number.

638378615857 is a deficient number, since it is larger than the sum of its proper divisors (3300488143).

638378615857 is a wasteful number, since it uses less digits than its factorization.

638378615857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 462975.

The product of its digits is 203212800, while the sum is 67.

The spelling of 638378615857 in words is "six hundred thirty-eight billion, three hundred seventy-eight million, six hundred fifteen thousand, eight hundred fifty-seven".