639885505 has 8 divisors (see below), whose sum is σ = 877557312. Its totient is φ = 438778608.

The previous prime is 639885497. The next prime is 639885509. The reversal of 639885505 is 505588936.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 639885505 - 2³ = 639885497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639885509) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9141187 + ... + 9141256.

It is an arithmetic number, because the mean of its divisors is an integer number (109694664).

Almost surely, 2^639885505 is an apocalyptic number.

It is an amenable number.

639885505 is a deficient number, since it is larger than the sum of its proper divisors (237671807).

639885505 is a wasteful number, since it uses less digits than its factorization.

639885505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18282455.

The product of its (nonzero) digits is 1296000, while the sum is 49.

The square root of 639885505 is about 25295.9582740010. The cubic root of 639885505 is about 861.7224829480.

The spelling of 639885505 in words is "six hundred thirty-nine million, eight hundred eighty-five thousand, five hundred five".