639688544227 has 4 divisors (see below), whose sum is σ = 661746769920. Its totient is φ = 617630318536.

The previous prime is 639688544221. The next prime is 639688544279. The reversal of 639688544227 is 722445886936.

It is a happy number.

639688544227 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-639688544227 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639688544221) 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, 11029112803 + ... + 11029112860.

It is an arithmetic number, because the mean of its divisors is an integer number (165436692480).

Almost surely, 2^639688544227 is an apocalyptic number.

639688544227 is a deficient number, since it is larger than the sum of its proper divisors (22058225693).

639688544227 is a wasteful number, since it uses less digits than its factorization.

639688544227 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22058225692.

The product of its digits is 139345920, while the sum is 64.

The spelling of 639688544227 in words is "six hundred thirty-nine billion, six hundred eighty-eight million, five hundred forty-four thousand, two hundred twenty-seven".