638005290 has 64 divisors (see below), whose sum is σ = 1672296192. Its totient is φ = 154828800.

The previous prime is 638005267. The next prime is 638005321. The reversal of 638005290 is 92500836.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16170 + ... + 39210.

It is an arithmetic number, because the mean of its divisors is an integer number (26129628).

Almost surely, 2^638005290 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638005290, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (836148096).

638005290 is an abundant number, since it is smaller than the sum of its proper divisors (1034290902).

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

638005290 is a wasteful number, since it uses less digits than its factorization.

638005290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23135.

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 638005290 is about 25258.7665969659. The cubic root of 638005290 is about 860.8776375001.

The spelling of 638005290 in words is "six hundred thirty-eight million, five thousand, two hundred ninety".