639174816 has 108 divisors (see below), whose sum is σ = 2114459802. Its totient is φ = 182617344.

The previous prime is 639174773. The next prime is 639174817. The reversal of 639174816 is 618471936.

It is a happy number.

639174816 is a `hidden beast` number, since 639 + 1 + 7 + 4 + 8 + 1 + 6 = 666.

It can be written as a sum of positive squares in only one way, i.e., 510579216 + 128595600 = 22596^2 + 11340^2 .

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 (639174817) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 8535 + ... + 36758.

Almost surely, 2^639174816 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 639174816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1057229901).

639174816 is an abundant number, since it is smaller than the sum of its proper divisors (1475284986).

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

639174816 is a wasteful number, since it uses less digits than its factorization.

639174816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45323 (or 45305 counting only the distinct ones).

The product of its digits is 217728, while the sum is 45.

The square root of 639174816 is about 25281.9068901062. The cubic root of 639174816 is about 861.4033406682.

The spelling of 639174816 in words is "six hundred thirty-nine million, one hundred seventy-four thousand, eight hundred sixteen".