638636580865 has 8 divisors (see below), whose sum is σ = 772398259200. Its totient is φ = 506886356592.

The previous prime is 638636580863. The next prime is 638636580929. The reversal of 638636580865 is 568085636836.

It is a happy number.

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 638636580865 - 2¹ = 638636580863 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 638636580797 and 638636580806.

It is not an unprimeable number, because it can be changed into a prime (638636580863) 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, 502862815 + ... + 502864084.

It is an arithmetic number, because the mean of its divisors is an integer number (96549782400).

Almost surely, 2^638636580865 is an apocalyptic number.

It is an amenable number.

638636580865 is a deficient number, since it is larger than the sum of its proper divisors (133761678335).

638636580865 is a wasteful number, since it uses less digits than its factorization.

638636580865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1005727031.

The product of its (nonzero) digits is 149299200, while the sum is 64.

The spelling of 638636580865 in words is "six hundred thirty-eight billion, six hundred thirty-six million, five hundred eighty thousand, eight hundred sixty-five".