643130356221 has 10 divisors (see below), whose sum is σ = 960725593982. Its totient is φ = 428753570760.

The previous prime is 643130356181. The next prime is 643130356279. The reversal of 643130356221 is 122653031346.

643130356221 is a `hidden beast` number, since 6 + 43 + 1 + 30 + 3 + 562 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 626266476900 + 16863879321 = 791370^2 + 129861^2 .

It is not a de Polignac number, because 643130356221 - 2¹¹ = 643130354173 is a prime.

It is a super-3 number, since 3×643130356221³ (a number of 36 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643130256221) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 3969940390 + ... + 3969940551.

Almost surely, 2^643130356221 is an apocalyptic number.

It is an amenable number.

643130356221 is a deficient number, since it is larger than the sum of its proper divisors (317595237761).

643130356221 is an equidigital number, since it uses as much as digits as its factorization.

643130356221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7939880953 (or 7939880944 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 36.

Adding to 643130356221 its reverse (122653031346), we get a palindrome (765783387567).

The spelling of 643130356221 in words is "six hundred forty-three billion, one hundred thirty million, three hundred fifty-six thousand, two hundred twenty-one".