638611554778 has 16 divisors (see below), whose sum is σ = 1009011312000. Its totient is φ = 302297026752.

The previous prime is 638611554773. The next prime is 638611554829. The reversal of 638611554778 is 877455116836.

It is not an unprimeable number, because it can be changed into a prime (638611554773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5586658 + ... + 5699821.

It is an arithmetic number, because the mean of its divisors is an integer number (63063207000).

Almost surely, 2^638611554778 is an apocalyptic number.

638611554778 is a deficient number, since it is larger than the sum of its proper divisors (370399757222).

638611554778 is a wasteful number, since it uses less digits than its factorization.

638611554778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11287989.

The product of its digits is 33868800, while the sum is 61.

The spelling of 638611554778 in words is "six hundred thirty-eight billion, six hundred eleven million, five hundred fifty-four thousand, seven hundred seventy-eight".