638585220 has 384 divisors, whose sum is σ = 2359526400. Its totient is φ = 125411328.

The previous prime is 638585201. The next prime is 638585221. The reversal of 638585220 is 22585836.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (638585221) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 5858526 + ... + 5858634.

It is an arithmetic number, because the mean of its divisors is an integer number (6144600).

Almost surely, 2^638585220 is an apocalyptic number.

638585220 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 638585220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1179763200).

638585220 is an abundant number, since it is smaller than the sum of its proper divisors (1720941180).

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

638585220 is a wasteful number, since it uses less digits than its factorization.

638585220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207 (or 205 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 39.

The square root of 638585220 is about 25270.2437661373. The cubic root of 638585220 is about 861.1383968723.

The spelling of 638585220 in words is "six hundred thirty-eight million, five hundred eighty-five thousand, two hundred twenty".