638221248 has 224 divisors, whose sum is σ = 2257958400. Its totient is φ = 172689408.

The previous prime is 638221247. The next prime is 638221253. The reversal of 638221248 is 842122836.

638221248 is a `hidden beast` number, since 638 + 2 + 2 + 12 + 4 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (224).

It is a super-2 number, since 2×638221248² = 814652722797355008, which contains 22 as substring.

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

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638221247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 228436 + ... + 231212.

Almost surely, 2^638221248 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 638221248, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1128979200).

638221248 is an abundant number, since it is smaller than the sum of its proper divisors (1619737152).

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

638221248 is a wasteful number, since it uses less digits than its factorization.

638221248 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2824 (or 2808 counting only the distinct ones).

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

The square root of 638221248 is about 25263.0411470987. The cubic root of 638221248 is about 860.9747591819.

The spelling of 638221248 in words is "six hundred thirty-eight million, two hundred twenty-one thousand, two hundred forty-eight".