638358043338 has 80 divisors (see below), whose sum is σ = 1480886146080. Its totient is φ = 205286495904.

The previous prime is 638358043283. The next prime is 638358043339. The reversal of 638358043338 is 833340853836.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (638358043339) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 5974581 + ... + 6080487.

It is an arithmetic number, because the mean of its divisors is an integer number (18511076826).

Almost surely, 2^638358043338 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638358043338, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (740443073040).

638358043338 is an abundant number, since it is smaller than the sum of its proper divisors (842528102742).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

638358043338 is a wasteful number, since it uses less digits than its factorization.

638358043338 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107233 (or 107224 counting only the distinct ones).

The product of its (nonzero) digits is 14929920, while the sum is 54.

The spelling of 638358043338 in words is "six hundred thirty-eight billion, three hundred fifty-eight million, forty-three thousand, three hundred thirty-eight".