638401824 has 288 divisors, whose sum is σ = 2063880000. Its totient is φ = 193342464.

The previous prime is 638401793. The next prime is 638401831. The reversal of 638401824 is 428104836.

638401824 is a `hidden beast` number, since 638 + 4 + 0 + 18 + 2 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4284502 + ... + 4284650.

It is an arithmetic number, because the mean of its divisors is an integer number (7166250).

Almost surely, 2^638401824 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 638401824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1031940000).

638401824 is an abundant number, since it is smaller than the sum of its proper divisors (1425478176).

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

638401824 is a wasteful number, since it uses less digits than its factorization.

638401824 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 222 (or 202 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 36.

The square root of 638401824 is about 25266.6148108527. The cubic root of 638401824 is about 861.0559518811.

The spelling of 638401824 in words is "six hundred thirty-eight million, four hundred one thousand, eight hundred twenty-four".