638181376 has 112 divisors (see below), whose sum is σ = 1509857280. Its totient is φ = 263946240.

The previous prime is 638181373. The next prime is 638181389. The reversal of 638181376 is 673181836.

It is a tau number, because it is divible by the number of its divisors (112).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638181371) 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, 1777485 + ... + 1777843.

Almost surely, 2^638181376 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 638181376, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (754928640).

638181376 is an abundant number, since it is smaller than the sum of its proper divisors (871675904).

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

638181376 is an equidigital number, since it uses as much as digits as its factorization.

638181376 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 423 (or 399 counting only the distinct ones).

The product of its digits is 145152, while the sum is 43.

The square root of 638181376 is about 25262.2519977931. The cubic root of 638181376 is about 860.9568294015.

The spelling of 638181376 in words is "six hundred thirty-eight million, one hundred eighty-one thousand, three hundred seventy-six".