638671684896 has 480 divisors, whose sum is σ = 2225633034240. Its totient is φ = 175815360000.

The previous prime is 638671684879. The next prime is 638671684909. The reversal of 638671684896 is 698486176836.

638671684896 is a `hidden beast` number, since 6 + 3 + 86 + 7 + 1 + 68 + 489 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 134426521 + ... + 134431271.

It is an arithmetic number, because the mean of its divisors is an integer number (4636735488).

Almost surely, 2^638671684896 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 638671684896, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1112816517120).

638671684896 is an abundant number, since it is smaller than the sum of its proper divisors (1586961349344).

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

638671684896 is a wasteful number, since it uses less digits than its factorization.

638671684896 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5050 (or 5033 counting only the distinct ones).

The product of its digits is 501645312, while the sum is 72.

It can be divided in two parts, 63867168 and 4896, that added together give a square (63872064 = 7992²).

The spelling of 638671684896 in words is "six hundred thirty-eight billion, six hundred seventy-one million, six hundred eighty-four thousand, eight hundred ninety-six".