638223768 has 288 divisors, whose sum is σ = 2192486400. Its totient is φ = 164166912.

The previous prime is 638223731. The next prime is 638223797. The reversal of 638223768 is 867322836.

638223768 is a `hidden beast` number, since 638 + 2 + 2 + 3 + 7 + 6 + 8 = 666.

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

It is a congruent 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 71 ways as a sum of consecutive naturals, for example, 5025321 + ... + 5025447.

It is an arithmetic number, because the mean of its divisors is an integer number (7612800).

Almost surely, 2^638223768 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 638223768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1096243200).

638223768 is an abundant number, since it is smaller than the sum of its proper divisors (1554262632).

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

638223768 is a wasteful number, since it uses less digits than its factorization.

638223768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 231 (or 211 counting only the distinct ones).

The product of its digits is 580608, while the sum is 45.

The square root of 638223768 is about 25263.0910222799. The cubic root of 638223768 is about 860.9758923592.

The spelling of 638223768 in words is "six hundred thirty-eight million, two hundred twenty-three thousand, seven hundred sixty-eight".