639433872 has 320 divisors, whose sum is σ = 2342707200. Its totient is φ = 162155520.

The previous prime is 639433871. The next prime is 639433877. The reversal of 639433872 is 278334936.

639433872 is a `hidden beast` number, since 639 + 4 + 3 + 3 + 8 + 7 + 2 = 666.

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

It is not an unprimeable number, because it can be changed into a prime (639433871) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1563204 + ... + 1563612.

It is an arithmetic number, because the mean of its divisors is an integer number (7320960).

Almost surely, 2^639433872 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 639433872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1171353600).

639433872 is an abundant number, since it is smaller than the sum of its proper divisors (1703273328).

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

639433872 is a wasteful number, since it uses less digits than its factorization.

639433872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 491 (or 479 counting only the distinct ones).

The product of its digits is 653184, while the sum is 45.

The square root of 639433872 is about 25287.0297188104. The cubic root of 639433872 is about 861.5196998433.

The spelling of 639433872 in words is "six hundred thirty-nine million, four hundred thirty-three thousand, eight hundred seventy-two".