638818341658 has 32 divisors (see below), whose sum is σ = 1166643555840. Its totient is φ = 256244906160.

The previous prime is 638818341631. The next prime is 638818341671. The reversal of 638818341658 is 856143818836.

It is a junction number, because it is equal to n+sod(n) for n = 638818341596 and 638818341605.

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, 14445228 + ... + 14489383.

It is an arithmetic number, because the mean of its divisors is an integer number (36457611120).

Almost surely, 2^638818341658 is an apocalyptic number.

638818341658 is a deficient number, since it is larger than the sum of its proper divisors (527825214182).

638818341658 is a wasteful number, since it uses less digits than its factorization.

638818341658 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28934722.

The product of its digits is 26542080, while the sum is 61.

The spelling of 638818341658 in words is "six hundred thirty-eight billion, eight hundred eighteen million, three hundred forty-one thousand, six hundred fifty-eight".