639863424 has 192 divisors, whose sum is σ = 1933308000. Its totient is φ = 202868736.

The previous prime is 639863407. The next prime is 639863429. The reversal of 639863424 is 424368936.

639863424 is a `hidden beast` number, since 6 + 3 + 9 + 8 + 634 + 2 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (192).

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

It is a self number, because there is not a number n which added to its sum of digits gives 639863424.

It is not an unprimeable number, because it can be changed into a prime (639863429) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3574567 + ... + 3574745.

Almost surely, 2^639863424 is an apocalyptic number.

639863424 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639863424, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (966654000).

639863424 is an abundant number, since it is smaller than the sum of its proper divisors (1293444576).

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

639863424 is a wasteful number, since it uses less digits than its factorization.

639863424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 335 (or 320 counting only the distinct ones).

The product of its digits is 746496, while the sum is 45.

The square root of 639863424 is about 25295.5218171122. The cubic root of 639863424 is about 861.7125708033.

The spelling of 639863424 in words is "six hundred thirty-nine million, eight hundred sixty-three thousand, four hundred twenty-four".