638745585547836 has 384 divisors, whose sum is σ = 1866855558113280. Its totient is φ = 167606712041472.

The previous prime is 638745585547757. The next prime is 638745585547903.

638745585547836 is nontrivially palindromic in base 10.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 21686930086 + ... + 21686959538.

It is an arithmetic number, because the mean of its divisors is an integer number (4861603015920).

Almost surely, 2^{638745585547836} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638745585547836, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (933427779056640).

638745585547836 is an abundant number, since it is smaller than the sum of its proper divisors (1228109972565444).

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

638745585547836 is a wasteful number, since it uses less digits than its factorization.

638745585547836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48245 (or 48243 counting only the distinct ones).

The product of its digits is 81285120000, while the sum is 84.

The spelling of 638745585547836 in words is "six hundred thirty-eight trillion, seven hundred forty-five billion, five hundred eighty-five million, five hundred forty-seven thousand, eight hundred thirty-six".