639589585681 has 4 divisors (see below), whose sum is σ = 639599944000. Its totient is φ = 639579227364.

The previous prime is 639589585597. The next prime is 639589585697. The reversal of 639589585681 is 186585985936.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 639589585681 - 2²⁷ = 639455367953 is a prime.

It is a super-2 number, since 2×639589585681² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639589885681) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5085981 + ... + 5210218.

It is an arithmetic number, because the mean of its divisors is an integer number (159899986000).

Almost surely, 2^639589585681 is an apocalyptic number.

It is an amenable number.

639589585681 is a deficient number, since it is larger than the sum of its proper divisors (10358319).

639589585681 is a wasteful number, since it uses less digits than its factorization.

639589585681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10358318.

The product of its digits is 559872000, while the sum is 73.

The spelling of 639589585681 in words is "six hundred thirty-nine billion, five hundred eighty-nine million, five hundred eighty-five thousand, six hundred eighty-one".