638143968 has 192 divisors, whose sum is σ = 2107607040. Its totient is φ = 164236800.

The previous prime is 638143963. The next prime is 638143981. The reversal of 638143968 is 869341836.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638143963) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 968023 + ... + 968681.

It is an arithmetic number, because the mean of its divisors is an integer number (10977120).

Almost surely, 2^638143968 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 638143968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1053803520).

638143968 is an abundant number, since it is smaller than the sum of its proper divisors (1469463072).

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

638143968 is a wasteful number, since it uses less digits than its factorization.

638143968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 821 (or 813 counting only the distinct ones).

The product of its digits is 746496, while the sum is 48.

The square root of 638143968 is about 25261.5115937269. The cubic root of 638143968 is about 860.9400069622.

The spelling of 638143968 in words is "six hundred thirty-eight million, one hundred forty-three thousand, nine hundred sixty-eight".