639660241 has 16 divisors (see below), whose sum is σ = 751394880. Its totient is φ = 538017280.

The previous prime is 639660209. The next prime is 639660257. The reversal of 639660241 is 142066936.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 639660241 - 2⁵ = 639660209 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 639660241.

It is not an unprimeable number, because it can be changed into a prime (639660041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17956 + ... + 40021.

It is an arithmetic number, because the mean of its divisors is an integer number (46962180).

Almost surely, 2^639660241 is an apocalyptic number.

It is an amenable number.

639660241 is a deficient number, since it is larger than the sum of its proper divisors (111734639).

639660241 is a wasteful number, since it uses less digits than its factorization.

639660241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58064.

The product of its (nonzero) digits is 46656, while the sum is 37.

The square root of 639660241 is about 25291.5053130493. The cubic root of 639660241 is about 861.6213513992.

The spelling of 639660241 in words is "six hundred thirty-nine million, six hundred sixty thousand, two hundred forty-one".