638821778115 has 16 divisors (see below), whose sum is σ = 1022660599968. Its totient is φ = 340523030016.

The previous prime is 638821778087. The next prime is 638821778149. The reversal of 638821778115 is 511877128836.

It is a happy number.

It is not a de Polignac number, because 638821778115 - 2⁵ = 638821778083 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11340864 + ... + 11397053.

It is an arithmetic number, because the mean of its divisors is an integer number (63916287498).

Almost surely, 2^638821778115 is an apocalyptic number.

638821778115 is a deficient number, since it is larger than the sum of its proper divisors (383838821853).

638821778115 is a wasteful number, since it uses less digits than its factorization.

638821778115 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22739798.

The product of its digits is 4515840, while the sum is 57.

The spelling of 638821778115 in words is "six hundred thirty-eight billion, eight hundred twenty-one million, seven hundred seventy-eight thousand, one hundred fifteen".