639595494221 has 6 divisors (see below), whose sum is σ = 645305733930. Its totient is φ = 633935344448.

The previous prime is 639595494211. The next prime is 639595494287. The reversal of 639595494221 is 122494595936.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 3766276900 + 635829217321 = 61370^2 + 797389^2 .

It is not a de Polignac number, because 639595494221 - 2¹⁸ = 639595232077 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639595494211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 25032086 + ... + 25057623.

It is an arithmetic number, because the mean of its divisors is an integer number (107550955655).

Almost surely, 2^639595494221 is an apocalyptic number.

It is an amenable number.

639595494221 is a deficient number, since it is larger than the sum of its proper divisors (5710239709).

639595494221 is an equidigital number, since it uses as much as digits as its factorization.

639595494221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50089935 (or 50089822 counting only the distinct ones).

The product of its digits is 20995200, while the sum is 59.

The spelling of 639595494221 in words is "six hundred thirty-nine billion, five hundred ninety-five million, four hundred ninety-four thousand, two hundred twenty-one".