638733648 has 80 divisors (see below), whose sum is σ = 1911691136. Its totient is φ = 179988480.

The previous prime is 638733637. The next prime is 638733649. The reversal of 638733648 is 846337836.

It is a Harshad number since it is a multiple of its sum of digits (48).

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

It is a junction number, because it is equal to n+sod(n) for n = 638733597 and 638733606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638733649) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 11508 + ... + 37548.

Almost surely, 2^638733648 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 638733648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (955845568).

638733648 is an abundant number, since it is smaller than the sum of its proper divisors (1272957488).

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

638733648 is a wasteful number, since it uses less digits than its factorization.

638733648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26132 (or 26126 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 48.

The square root of 638733648 is about 25273.1804092797. The cubic root of 638733648 is about 861.2051105723.

The spelling of 638733648 in words is "six hundred thirty-eight million, seven hundred thirty-three thousand, six hundred forty-eight".