639682560 has 288 divisors, whose sum is σ = 2422405440. Its totient is φ = 154828800.

The previous prime is 639682553. The next prime is 639682583. The reversal of 639682560 is 65286936.

It is a happy number.

639682560 is a `hidden beast` number, since 6 + 3 + 9 + 6 + 82 + 560 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1013445 + ... + 1014075.

It is an arithmetic number, because the mean of its divisors is an integer number (8411130).

Almost surely, 2^639682560 is an apocalyptic number.

639682560 is a gapful number since it is divisible by the number (60) 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 639682560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1211202720).

639682560 is an abundant number, since it is smaller than the sum of its proper divisors (1782722880).

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

639682560 is a wasteful number, since it uses less digits than its factorization.

639682560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 675 (or 652 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 45.

The square root of 639682560 is about 25291.9465443054. The cubic root of 639682560 is about 861.6313725021.

The spelling of 639682560 in words is "six hundred thirty-nine million, six hundred eighty-two thousand, five hundred sixty".