638628646826836 has 24 divisors (see below), whose sum is σ = 1117676715581664. Its totient is φ = 319292443157280.

The previous prime is 638628646826813. The next prime is 638628646826837.

638628646826836 is nontrivially palindromic in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 638628646826836.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638628646826837) 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, 5917393171 + ... + 5917501093.

It is an arithmetic number, because the mean of its divisors is an integer number (46569863149236).

Almost surely, 2^{638628646826836} is an apocalyptic number.

It is an amenable number.

638628646826836 is a deficient number, since it is larger than the sum of its proper divisors (479048068754828).

638628646826836 is a wasteful number, since it uses less digits than its factorization.

638628646826836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195591 (or 195589 counting only the distinct ones).

The product of its digits is 27518828544, while the sum is 82.

The spelling of 638628646826836 in words is "six hundred thirty-eight trillion, six hundred twenty-eight billion, six hundred forty-six million, eight hundred twenty-six thousand, eight hundred thirty-six".