638527968 has 144 divisors (see below), whose sum is σ = 2017113840. Its totient is φ = 196425216.

The previous prime is 638527961. The next prime is 638527979. The reversal of 638527968 is 869725836.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638527961) 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 23 ways as a sum of consecutive naturals, for example, 143830 + ... + 148202.

It is an arithmetic number, because the mean of its divisors is an integer number (14007735).

Almost surely, 2^638527968 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 638527968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1008556920).

638527968 is an abundant number, since it is smaller than the sum of its proper divisors (1378585872).

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

638527968 is a wasteful number, since it uses less digits than its factorization.

638527968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4418 (or 4391 counting only the distinct ones).

The product of its digits is 4354560, while the sum is 54.

The square root of 638527968 is about 25269.1109459751. The cubic root of 638527968 is about 861.1126611431.

The spelling of 638527968 in words is "six hundred thirty-eight million, five hundred twenty-seven thousand, nine hundred sixty-eight".