638534400 has 216 divisors, whose sum is σ = 2408845824. Its totient is φ = 145920000.

The previous prime is 638534381. The next prime is 638534437. The reversal of 638534400 is 4435836.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 132025 + ... + 136775.

It is an arithmetic number, because the mean of its divisors is an integer number (11152064).

Almost surely, 2^638534400 is an apocalyptic number.

638534400 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638534400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1204422912).

638534400 is an abundant number, since it is smaller than the sum of its proper divisors (1770311424).

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

638534400 is a wasteful number, since it uses less digits than its factorization.

638534400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4787 (or 4768 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 33.

The square root of 638534400 is about 25269.2382156645. The cubic root of 638534400 is about 861.1155525111.

The spelling of 638534400 in words is "six hundred thirty-eight million, five hundred thirty-four thousand, four hundred".